INTRODUCTION - Human Physiology



Clinical AnatomyPA 544Tony Serino, Ph.D.Associate Professor of BiologyMisericordia University ?2019 Tony Serino, Ph.D. TOC \o "1-1" \h \z Introduction PAGEREF _Toc175035652 \h 3Systems Overview PAGEREF _Toc175035653 \h 5The Head Region PAGEREF _Toc175035654 \h 14Endocrine System PAGEREF _Toc175035655 \h 20Neck PAGEREF _Toc175035656 \h 22Thorax: Chest ad Pleura PAGEREF _Toc175035657 \h 26Mediastinum PAGEREF _Toc175035658 \h 30Blood PAGEREF _Toc175035659 \h 35Excretory System PAGEREF _Toc175035661 \h 45Reproductive System PAGEREF _Toc175035662 \h 47Developmental Anatomy PAGEREF _Toc175035663 \h 6Upper Limb: Arm PAGEREF _Toc175035664 \h 8Lower Limb: Leg PAGEREF _Toc175035666 \h 9Appendix PAGEREF _Toc175035668 \h 10The Cell PAGEREF _Toc175035669 \h 11Metabolism PAGEREF _Toc175035670 \h 15Tissues PAGEREF _Toc175035671 \h 18Abbreviations of anatomical and medical terms used in coursea., aa. artery, arteriesANS autonomic nervous system IVC .inferior vena cavaant. anterior jt. joint Ao. aorta AP anteroposterior L, L. left or Latin (e,g., L, cauda, a tail) asc.ascending LA left atrium of the heart AVatrioventricular or arteriovenous- LADleft anterior descending (coronary artery)depending on the context lat. lateralb. bone LICS Left intercostal space-the apical impulse orheartbeat is usually heard and felt in the 4th or br. Branch5th LICSCl-C7(8) cervical vertebrae (C1-C7)/spinal cord lig., ligg. ligament, ligamentssegments and spinal nerves (C1-C8)LLQ left lower quadrant of the abdomenCA. cancer, carcinoma, or cardiac arrest- LP lumbar punctureDepending on contextCAD coronary artery disease LUQ left upper quadrant of the abdomen CAT computed axial tomography LV left ventricle of the heart CN. cranial nerve (e,g., CN VII, facial nerve) m., mm. muscle, muscles (when muscles are obvious Co. coccyx/coccygeal spinal cord segment; in an illustration or a medical image, the coccygeal spinal nerve abbreviation is usually omitted) com. common MAL midaxillary line CNS central nervous system MCL midclavicular line CSF cerebrospinal fluid CT computed tomographymed. medial desc. descending MI myocardial infarction-death of part of themyocardium (heart muscle) ECG/EKG electrocardiogram; electrocardiography MRImagnetic resonance imaging EEG electroencephalogram;MSL midsternal line electroencephalography MV mitral valve (the left A V valve)e.g. for example n., nn, nerve, nerves EMG electromyogram; electromyography PNS peripheral nervous system ext. extensor/external post. posterior G. Greek (e.g., G. zyon, yoke) R right (e.g. on a radiograph) GI gastrointestinal (e,g., GI tract) r., rr. ramus, rami (branch, branches) lMA or IMV inferior mesenteric artery or vein RA right atrium of the heart RICS right intercostal space inf. inferior RLQ right lower quadrant of the abdomen int. internal RUQ right upper quadrant of the abdomen IP intraperitoneally (e.g., an IP injection)RV right ventricle of the heartSl-S5 sacral vert./spinal cord segments/spinal nervessag. sagittalIV intravenoussup. superior I.V., intravenous or intravenouslyx.s.cross sectionKnow anatomical directions, planes of body, terms of movement and surface anatomy(pgs. 5-11)Introduction PRIVATE Anatomy –study of body structures and relationshipsPhysiology -study of the mechanisms by which the body functionsApproaches to AnatomySystemic –study the body by its systems (collections of organs carrying out a specific task); most common way to teach undergraduate anatomy coursesSystemMedical FieldIntegumentaryDermatologySkeletalOrthopedicsOsteologyJointsArthrologyMuscularMyologyNervousNeurologyCirculatoryAngiologyCardiovascular (heart)CardiologyDigestion (Alimentary)GastroenterologyRespiratoryPulmonologyUrinaryUrologyReproductiveGynecology or AndrologyEndocrineEndocrinologyRegional –method of studying body structures by focusing on a particular site or region including all of its systemic features; allows understanding of 3D arrangement and relationships between structuresSurface Anatomy –study of body surface referencing what lies beneath surface; useful in visualization of internal parts (vital in physical examination with palpation, in medical diagnosis and treatments)Clinical –emphasizes structure and functional relationships important to the practice of medicineAnatomical Plan and Characteristics:Tube within a tube.-External vs. Internal environment-body cavities: ventral cavities: peritoneal, pericardial, pleural; dorsal: CNS cavities.-mesothelium: mesenteries (true vs. ligaments). Parietal vs. Visceral-serous fluidsBilateral SymmetryAnatomical Directions and Position-The Anatomical Position: standing erect with head and feet directed forward and arms by side with palms facing forward (thumbs out)-Read pages in book on anatomical planes, sections, direction and movement (including figures)Dorsal Hollow Nerve CordAnatomical VariationsPhysiological PlanHomeostasis -maintenance of a constant internal environment, accomplished by reflex arcs which monitor deviations from a set point for a particular variable (i.e. temperature, BP, etc.); carried out mostly by nervous and endocrine systemsReflex -is usually a built-in response to a stimulus (which is any detectable change in the environment):Stimulus Receptor (sensor) afferent path Integrating Center /|\| | (usually negative) | | \|/ Response Effector (muscle or glands) efferent pathNegative Feedback -response which opposes the stimulus (most common)Positive Feedback -response which increases the stimulus furtherMost parameters in the body are controlled by several effectors operating antagonistically to one anotherFactors which affect Homeostasis:Feed-forward regulation -anticipates changes in the environment and responds before the change actually occursAcclimatization -enhancement of response due to prolonged exposureBiorhythms -internally driven cyclesInternal Environment:60-90% water, 18% protein, 15% fat, 7% mineral of body weight63% hydrogen, 25% oxygen, 9.5% carbon, 1.4 % nitrogen (=99%)<1% Minor elements: Ca, P, Cl, K, S, Na, MgTrace elements (<0.01%): Fe, Fl, Zn, I, Co, Mn, Cr, etc.Body Fluid CompartmentsExtracellular fluid (ECF): that fluid contained within the skin but external to cells; makes up about 1/3 of the total body waterA. Interstitial fluid -that fluid bathing all cells outside of the bloodstream; 15% body weightB. Blood Plasma -the fluid component of the bloodstream; 5% body weightIntracellular fluid -fluid found within cell membranes; makes up 2/3 of the total body water; 40% of body weightTranscellular fluids -fluids which appear to be outside but connected to the ECF; such as: CSF, fluids in the eye, glandular secretions, etc. The volume of these fluids is exceedingly small.Systems Overview Integument (Skin)main functions: protection, thermoregulation, sensory, excretory, muscle attachment, homeostasis, phermonal secretionsAnatomy of Human Skin-composed of and epithelial layer (epidermis) and underlying CT supporting layer (dermis)Epidermis-composed of 4-5 layers of keratinocytes (stratified squamous epithelium) Interspersed with melanocytes, Merkels discs, and Langerhans cells; the layer is avascular and is therefore dependent on the blood supply of the dermis for nourishment; review layers of epidermis: Stratum basale, spinosum, granulosum, lucidum and corneumDermis-composed mainly of connective tissue with many fibers (esp. collagen and elastin); account for skin strength and elasticity also tension lines important in surgery. Collagen fibers tend to run in parallel arrangements and produce characteristic tension lines and wrinkles in the skin. These Tension Lines (cleavage or Langer’s lines) tend to run circumferentially in the trunk and neck and longitudinally in the limbs. Surgical incisions made in the direction of these lines have less tendency to gape, suture more easily and produce less scarring.Divided into 2 layers:1. Papillary layer -region of dermal papillae; many touch receptors (Meissner's corpuscles)2. Reticular layer -composed of dense nets of collagen and elastic fibers interspersed with adipose, hair follicles, nerves, sebaceous (oil) glands, sweat glandsSubcutaneous layer (hypodermis, superficial fascia) –composed of loose areolar CT and adipose, but varies widely anatomically; contains nerve endings for deep pressure (Pacinian corpuscles) and sweat glands and many blood vessels -attaches skin to underlying structures, provides cushion effect, and thermoregulates bodySkin ligaments(ligamentum retinacula cutis) –numerous small fibrous bands which connect the deep dermis to the underlying deep fascia (CT which surrounds muscles); well developed in breasts (suspensory ligaments) and in the palms and solesRead about stretch marks and burns.Epidermal derivatives1. Nails -modification of SC tipping the digits2. Hair -char. of mammals; insulation and sensory functions -anatomy; terms: hair shaft, hair follicle, arrector pili, sebaceous glandsEpidermal glands:General gland classification: Structural and Functional classification. Types found in mammals:1. Sebaceous (oil)2. Sudoriferous (sweat)3. Ceruminous (wax) 4. Mammary (milk)Skeletal Systemcomposed of:-mineralized Connective Tissue (CT) found in bone and cartilage, and their associated CT support structures: ligaments, tendons and bursaefunctions:-support, protection, movement, homeostasis (Ca++ regulation), hemopoiesis General Osteology-mineralized CT composition:1. Cells -originate from undifferentiated mesoderm cells2. Extracellular matrixa) ground substances:- water (primarily), glycosaminoglycans (GAG) -cementing substance; salts (primarily Ca++ salts -hydroxyapatite in bone); glycoproteins (eg. chondroitin sulphate in cartilage)b) fibers (collagen and elastin)Cartilage: Anatomy of hyaline cartilage: chondroblasts, chondrocytes, lacunae, perichondrium Types: (based on most abundant fiber type present)1. fibrocartilage (collagen) -ex. pubic symphysis, intervertebral disc2. elastic cartilage (elastin) -ex. epiglottis, pinna3. Hyaline (more ground substance than fibers) -most common type -articular surfaces of long bones, ends of ribs Growth: appositional (at periphery) and interstitial (from within)Bone:-Haversian systems (osteons)anatomy: osteocytes, osteoblasts, osteoclasts, lacunae, canaliculi, Haversian canals, Volkmann's canals, lamellae-Anatomy of mammalian long bone:terms: -diaphysis, epiphysis, metaphysis, epiphyseal plate, periosteum, endosteum, medullary (marrow) cavity {with yellow and red marrow}, compact, spongy, trabeculae-Development:A. premature bone = woven bone (first bone generated)B. mature bone = spongy or compact bone (either may replace woven bone)Ossification:1. Intramembranous (membrane bone) -bone directly replaces preskeletal mesodermal membrane; no intervening cartilage model2. Endochondral (replacement bone) -preskeletal mesodermal membrane replaced by cartilage model first, then bone replaces the cartilage model; terms: nutrient artery, primary and secondary ossification centersGrowth: appositional only;four zones of the epiphysis:1. reserve cartilage zone -small chondrocytes which anchor plate to epiphysis2. proliferating cartilage zone -actively dividing chondrocytes3. hypertrophic cartilage zone -chondrocytes increasing in size4. calcified matrix zone -most chondrocytes dead; matrix being replaced by boneDivisions of Skeletal SystemAxial -notochord, vertebra, ribs, sternum, skull and visceral archesAppendicular -pectoral and pelvic girdles, and the limbsTypes of bones: -long, short, flat, irregular, wormian, sesamoid, and heterotropic bonesRead Bone Markings and FormationsArticulationsFunctional classifications:1. Synarthrotic -immovable (ex. sutures, synchondroses, gomphoses)2. Amphiarthrotic -slightly immovable (ex. syndesmoses, symphyses)3. Diarthrotic -freely movable (gliding, hinge, pivot, ellipsoidal, saddle, and ball-n-socket)(see figure in book and be able to identify types)Structural Classification:1. Fibrous -no synovial cavity, held together by fibrous CTex. sutures, syndesmoses, gomphoses2. Cartilaginous -no synovial cavity, connected by cartilageex. symphyses, synchondroses3. Synovial -synovial cavity present-anatomy: synovial membrane, fibrous capsule, articular capsule, articular cartilage (menisci -in knee) ex. same as diarthrotic jointsTendons, Ligaments and Bursae-composed of fibrous CT-tendon -connects muscle to bone-ligament -connects bone to bone-bursae -resemble synovial membranes and filled with fluid; decrease friction between bone, muscles, tendons, ligaments and skinAging-loss of water (primarily)-loss of Ca++-decrease in protein synthesis for matrix leading to bone brittlenessMuscular Systemhas the ability to contract; therefore functions in the movement of the body, its parts, and the contents within the body; three types:a. Skeletal -muscle which moves the skeleton; voluntary and striated-origin, insertion, action-Muscle architecture: See book-long, cylindrical (non-branching), striated, multinucleated cells; muscle cell = muscle fiberappear striated; due to arrangement of contractile proteins (actin and myosin); arranged in bundles known as myofibrils-10-100 um in diameter; up to 35 cm in length-voluntary, no spontaneous contractility-Know Histology of muscle fiber: sarcosomes, sarcolemma, sarcoplasm, sarcoplasmic reticulum (SR), triads, motor unit and T-tubules-innervated by motor neurons with acetylcholine (ACh) as the neurotransmitter-nuclei displaced to side of cell due to arrangement ofmyofibrils (contractile proteins)develop from fusion of myoblasts; satellite cells remain as reserve; -each cell is wrapped in a CT sheath (endomysium) and aggregates of cells are grouped into bundles (fascicles) surrounded by another CT sheath (perimysium); the whole muscle is bound by CT sheath (epimysium) which is continuous with the tendon. This arrangement allows the efficient transmission of force across the tendon; and adds the elasticity of the tendon and CT sheaths to the muscle (known as series elastic component) (note: limited stretching of whole muscle—generally cannot be stretched >1/3 their length without damage (results in muscle pull (or tear))-almost all whole muscles are antagonistically arranged (that is; each group pair has the opposite action; for example: flexor and extensor). It is combination of this arrangement and the series elastic component which allows a muscle to return to its original length, without these a muscle cell would remain shortened after contraction.Physiology of Contraction (Sliding Filament Theory)1. A motor neuron fires and secretes ACh across neuromuscular junction2. ACh triggers a depolarization of sarcolemma which quickly spreads to all parts of cell including deep inside cell via T-tubules3. The depolarization allows Ca++ to escape from SR4. Ca++ binds to troponin which pivots tropomyosin out of actin's trench exposing actin's myosin binding site5. Myosin crossbridge binds to actin; ATP supplies energy for swivel of crossbridge6. ATP used to release myosin and actin; and crossbridge snaps back7. Steps 5 and 6 are repeated as long as Ca++ bond to troponin8. SR pumps Ca++ back if no longer stimulatedTypes of skeletal muscle fibers:-based on myoglobin content and the rates of ATP generation and splitting1. slow twitch red fibers2. fast twitch red fibers3. fast twitch white fibersb. Cardiac -muscle in the heart, involuntary and striated-involuntary, striated, spontaneous contractility (autorhythmic)-long cylindrical, branching cells with 1-2 nuclei centrally located; the cells are joined to one another by intercalated discs-the discs anchor the myofibrils and spread the depolarization wave between cells-contraction not dependent on outside stimulus; the autonomic nervous system (ANS) and hormones regulate rate of contraction only-the ANS innervates special "pacemaker" regionsc. Smooth -associated with tubes and ducts, involuntary and non-striated, spindle shaped cells-autorhythmic: specialized for continuous contraction (the latch state with tension maintained without energy consumption and can adapt to new length when stretched instead of contracting continuously against the stretch-contraction controlled by enzymatic process-contractions modulated by ANS, hormones and local metabolites-can mitotically divide and even take on characteristics of other mesodermal tissues-associated with internal environments-organs, vessels, ducts, arrectors of hair-KNOW differences of myofibril arrangement-Types:1. visceral (single unit)2. multiunitCardiovascular System- moves the blood-two circuit system (systemic and pulmonary); arteries move blood away from the heart; veins move blood toward the heart-the flow of blood is usually:artery arterioleheart capillariesveins venules-consists of a closed system of vessels which transports the blood. It includes the heart, arteries (elastic and muscular), arterioles, capillaries, venules, and veins.-the arterioles, venules and capillaries make up the microcirculationBlood Vessels:-arteries conduct blood away from the heart and veins conduct blood to the heart-80% of the blood found in veins, 20% in the arteriesStructure of Arteries and Veins-consist of at least 3 layers or coats (called tunics)Tunica interna (intima) -an endothelium and BMTunica media -a smooth muscle layer and elastic CTTunica externa (adventitia)– an outer dense connective tissue layerKnow differences between artery and vein layersArterioles -small arteries which feed capillaries, metarterioles or arterial-venular shunts;- major resistance vessels of vascular bed (maintain high blood press. when ventricles of heart relax) by controlling their diameter (total peripheral resistance, TPR) and their rhythmic pulsing; their smooth muscles are controlled by the sympathetic system, local agents and hormones. Capillaries -(7-10 mcm in dia) site of cellular exchange due to:1. thin wall -endothelium + BM only2. large surface area3. slow flow-exchange regulated by Starling Forces; which is the difference between the osmotic pressure of blood and tissues and the hydrostatic pressure of blood and tissuesVeins and venules -most have one way valves which prevent back flow of blood; and also contribute to blood flow in the veins by aiding the skeletal muscle pump.-large veins may act as blood reservoirs (capacitance vessels which can modify venous return through increased muscle tone; and therefore, modify Cardiac Output)Lymphatic SystemReturns tissue fluid to plasma for recirculation, this fluid (lymph fluid) is filtered before returning to the venous systemLymph Organs -spleen, thymus, tonsils, nodes and a variety of other diffuse sitesfunction in immune response and in WBC maturationLymph Vessels -have semilunar valves to prevent back flow; ultimately drain back into veins in chest; lymph is pumped mainly by skeletal muscle pumping (similar to veins)-The two largest lymphatic vessels (the right lymphatic vessel and the thoracic duct return the lymph to circulation by dumping the lymph in the junction of the subclavian and jugular veinslymph capillaries -blind fenestrated tubes lined by endothelium with no BM (only anchoring filaments); allow tissue fluid to automatically flow into capillary-not found in avascular tissue, CNS, teeth, bone, splenic pulp or bone marrowLymph Nodes -filters the lymph and are a primary site for WBC differentiation-bean shaped organs located along the length of lymphatic vessels-found clustered in specific regions of the body-afferent lymphatic vessels enter on the convex surface of the node and usually a single large efferent lymphatic vessel exits at the indentation of the node (hilum)-each node is covered by a fibrous capsule with an outer cortex and an inner medulla region-the cortex contains areas of densely packed lymphocytes called lymph nodules at the center of which activated lymphocytes are produced; this area is a germinal center-extensions of the fibrous capsule divides the node into many sinuses along which lymphocytes and macrophage are arranged; as the lymph flows through; the macrophage remove foreign material and cellular debris while lymphocytes are brought into contact with antigens (put simply the lymph is filtered)Functions: lymph filtration and T and B-cell activation through exposure to antigensLymph filtration: accomplished by macrophage anchored in sinusesT and B cell activation: macrophage and dendritic cells of cortex present antigens to lymphocytes-T cells generally activate in the cortex sinusoids between the nodules while B-cells activate within the germinal centers of secondary nodules-activated T-cells then leave the nodes to return to circulation, while activated B-cells and plasma cells migrate to the nodes medulla and begin secreting Ab (IgG)Nervous SystemFUNCTIONS:Sensory (afferent) -perceives the internal and external environmentIntegrative -interprets all sensory input (and memory) and initiates the efferent pathwayMotor (efferent) -elicits a response to the environment by stimulating an effector-response to stimulus is rapidDivisions of the Nervous SystemA. Central Nervous System (CNS) -brain and spinal cord (integrating centers)B. Peripheral Nervous system (PNS) -outside CNS1. Afferent (Sensory) system - conveys info to CNS2. Efferent (Motor) System -conveys away from the CNS i. Somatic Nervous system -to voluntary effectors (skeletal muscle) ii. Autonomic Nervous System (ANS) -to involuntary effectors (smooth muscle, cardiac, glands, etc.); consists of post- and pre-ganglionic fibersa. Parasympathetic -rest and repose (ACh - acetylcholine)b. Sympathetic -fight or flight (NE - norepinephrine)Nervous TissueNon-Excitable Tissue Involved in Nervous SystemA. Neuroglia (glia cells) 1. Macrogliaa. Ependymal cells -line the cavities of CNSb. Oligodendrocytes -secrete myelin in CNSc. Astrocytes -maintain brain blood barrier (BBB)-Protoplasmic and Fibrous 2. Microglia -phagocytic; clean CNS of debris(infection)B. Schwann Cells -secrete myelin in PNSC. Terms: ganglia, nuclei, nerve vs. nerve fiber, tracts, endo-, peri-, and epineuriumNeuron (cellular unit of nervous system)A. Structures of the Typical Neuron-Dendrites, Cell Body (Perikaryon), Axon Hillock, Initial Segment, Axon (+ Collaterals), Axon terminals, Synaptic Knobs (end bulbs), Myelin Sheath B. Internal Structures-synaptic vesicles C. Functionally Four Important Zones1. Receptor zone2. Initial segment 3. Axon 4. Nerve endingsTypes of NeuronsA. AnatomicallyB. Functionally-Unipolar (pseudo-unipolar)-Sensory (Afferent)-Bipolar-Motor (Efferent)-Multipolar-Association (Interneurons)Anatomy of a Synapse two kinds: chemical and electrical (gap junctions)Chemical: structures include pre and post -synaptic neurons, synaptic vesicles with neurotransmitter (NT) substances, synaptic cleft and receptors-allow one way transmission of signal (neurotransmission)-an electrical signal (AP) descends the axon and stimulates the synaptic knob to allow Ca++ to enter the cell; this triggers the synaptic vesicles to fuse with the membrane and dump their contents into the cleft. The NT diffuses across and binds with a receptor on the post-synaptic neuron which may eventually stimulate the postsynaptic neuron to fire.-neurotransmission is stopped by: a) diffusion of NT away from the synapse; b) re-uptake of NT into pre-synaptic terminal or c) metabolism of NT-examples of NT: acetylcholine from acetyl-CoA and choline; deactivated by enzyme in cleft and re-absorption of cholineReview the following material acquired in pre-requistie course work (know for test):MEMBRANE POTENTIALS -the unequal distribution of charge across the membrane resulting in a negative charge inside compared to outside the cell -due to the net movement of ions across the membrane; they move due to their concentration and electrical gradients; the presence of non-diffusible negatively charged particles inside the cell (proteins) and the Na+/K+ ATPase pump-the different distribution of charge across the membrane is expressed in millivolts (mV)(voltage = potential)Resting Membrane Potential -found in all cells (at rest, with respect to neurons or muscle)-ranges from -5 to -100 mV (-70 mV average for neurons) (negative because cell cytoplasm has excess negative charge)-exists due to the permeability of mainly K+ and the action of the Na-K pump (which pumps out 3 Na+ for every 2 K+) this helps generate a potential differencedefinitions commonly used:-depolarized -when membrane potential becomes less negative-hyperpolarized -the membrane potential becomes more negative-repolarizing -movement of membrane potential toward the resting potential after depolarizingGraded Potentials -transient, local changes in the membrane potential in either direction and is decremental -can be temporally or spatially summated (they add and subtract from each other) -can be excitatory (EPSP -excitatory post-synaptic potential) (depolarizing) trigger Na+ gates to open or inhibitory (IPSP) (hyperpolarizing) trigger more K+ (or Cl-) gates to open; can be used for postsynaptic and presynaptic inhibition -sensory receptors (such as touch, taste, etc.) elicit generator potentials which are graded potentialsAction Potentials -wave-like depolarization of an axon which self propagates down the axon (or along muscle cell membrane) has several components:-Foot: area of curve representing graded potential moving the cell body membrane closer to the threshold potential of the initial segment; nerve cells receive 1000's of signal, but will not generate an action potential unless its threshold firing level is reached-Uplimb: Na+ channels begin opening due to a positive feedback system until all channels are open (increases Na+ permeability into the cell); since all Na+ channels are open the AP reaches a maximum depolarization (about +40 mV), that is, AP amplitude is independent of the strength of stimulus; it obeys the All or None Law-Downlimb: the depolarization of the membrane also triggers K+ channels to open but these open more slowly than Na+, the flow of K+ repolarizes the cell because positive ions are allowed to flow out of the cell returning the cell interior to a more negative condition; also the Na-K pump is working throughout this cycle to repolarize the cell-After-hyperpolarization -small over-shoot by repolarizing forces which is corrected as gates (esp. K+) are reset and the pump re-establishes the ion gradientsRefractory Periods -time of neuron decreased excitability -absolute -neuron incapable of generating an AP (occurs while Na is moving) (uplimb and 1st third of downlimb) -relative -a strong stimulus (suprathreshold) may elicit an AP (rest of downlimb until potential is below threshold)Action Potential Propagation -movement of AP down axon -under natural conditions it always travels from the initial segment to the nerve endings -velocity of conduction depends on myelination and axon diameter The Head Region-skull, face, scalp, brain, cranial nerves, meninges, special sense organs, and oral cavity Bony Structure and Surface AnatomySkull: neurocranium (cranial vault) and facial skeleton (cranium usually refers to a skull without a mandible-the neurocranium divided into calvaria and cranial floor-know the basic bone structure of the skull (see figures in book)-Review major bones and Landmarks (mastoid, styloid, occipital eminence, sutures (coronal, squamosal, sagittal, lambdoidal, metopic))Other important surface markings:supercillary arches -sharp ridge above supraorbital marginlambda –junction of occipital and parietal bones (area of fetal posterior fontanelle)bregma –junction of frontal and parietal bones (area of fetal anterior fontanelle)asterion –point where occipital, parietal and temporal bones meet (mastoid fontanel)pterion –junction of sphenoid, temporal, parietal and frontal bones (area of fetal anteriolateral (sphenoid) fontanelle; overlies anterior branches of middle meningeal vessels (found with one thumb posterior to frontal process of zygomatic bone and two fingers superior to zygomatic archvertex –most superior portion of skull when oriented in Frankfort planenasion –point where frontal and nasal bones meetglabella –smooth prominence on frontal bone above nasion; most anterior projecting part of neurocraniuml-See Table in book Foramen and their contents-Internal structures: cribiform plate, sella turcica, petrous ridgeFetal Development: endochondral at base and intramembranous for calvariaNote: Frontal, Intermaxillary and Intermandibular sutures, and the 6 fontanellesFontannelles allow skull calvaria to move during birth; useful to physicians for monitoring growth of skull, degree of hydration and level of intercranial pressure-Anterior Fontanelle –site of bregma, not palpable by 18 mos.-Posterior Fontanelle –site of lambda, fuses by 2-3 months, completed by end of 1st year-Frontal Suture –slowly fuses starting in 2nd year and finished in 8th; 8% show metopic suture-Mandible –consists of 2 halves in newborn connected by fibrous joint, joint fuses in 1st year and done by end of 2nd year; contains 5 pairs of deciduous teeth, begin to erupt at ~ 6mos.; permanent teeth (8 pairs) begin to erupt at 6 years and finish in late puberty-obliteration of sutures in adults begins on the inside of skull at 30-40 years (10 years later outside begins to disappear); begins at bregmaScalp –skin and subcutaneous tissues covering the clavaria; covers from the superior nuchal line to the supraorbital margins; laterally to the zygomatic arches-consists of 5 layers the outer three remain connected and move as a unit:SCALP: Skin, Connective tissue (thick subcutaneous layer), Aponeurosis (tendinous sheath connecting parts of the epicranius muscle, Loose CT with many potential spaces (allows outer layers to move freely), and the Pericranium (periosteum of calvaria)Face –ranges from forehead to chin; and from ear to ear-skin held in place by skin ligaments to bones with no deep fascia (makes skin of face very loose (tends to gape when lacerated and prone to intense swelling when injured)-facial muscles lie subcutaneously, and attach to bones and skin; all developed from 2nd pharyngeal arch and supplied by CN VII (Facial)-CN V (trigeminal)–supplies the sensory nerves for the face and motor nerves for mastication-divides into 3 peripheral nerves of face (V1,V2, V3)V1 (Ophthalmic nerve) –tactile sense to eyeball, forehead and superior nasal area-exits skull through superior orbital fissureV2 (Maxillary nerve) –sensory to maxillary area and upper teeth-exits through foramen rotundumV3 (Mandibular nerve) –sensory to mandible (enters mandible through mandibular foramen) and lower teeth; touch reception in tongue; motor supply to mastication muscles (masseter, temporal, pterygoids and ant. belly of diagastric) and parotid-exits skull through foramen ovale-CN VII (facial) –motor supply for facial expression muscles, sublingual and submandibular glands; sensory near skin of acoustic area and anterior 2/3 of tongue taste buds-exits interior skull through internal acoustic meatus and then exterior through stylomastoid foramenVascular Supply-most blood supplied by facial artery (a branch of the external carotid) with many anastomosies-venous drainage through either internal or external jugular veins-note: cavernous sinus-all lymph from head and neck drains into the deep cervical lymph nodes which then drain into the jugular lymphatic trunk which joins the thoracic duct on the left side or the IJV or Brachiocephalic vein on the right sideOrbits –contains and protects the eyeball and accessory structures-periosteum of skull in orbit forms a fascia sheath around eyeball (periorbital)-orbit wall a combination of skull bones, with a very thin medial and inferior wall; apex of the orbit is the optic foramen-accessory structures:-eyebrow -protect eyes from objects, perspiration and light-eyelids -protect eyes from particles, injury, desiccation and excessive light; consist of thin skin covering bands of CT (tarsal plates) and covered internally by a palpebral conjunctiva (this is reflected over the surface of the eye as the bulbar conjunctiva and connects to the edges of the cornea). Embedded in the tarsal plate are tarsal (meibomian) glands and ciliary (Zeiss) glands (sebaceous glands of the eyelashes). Other terms to know: canthus (angle), conjunctival fornices (sacs). Eyelid operated by the levator palpebrae superioris (innervated by the CN III (oculomotor n.) and the orbicularis oculi (innervated by CN VII)-lacrimal apparatus -lacrimal gland and associated ducts creates and drains tearslacrimal gland –creates tears and is located in the lacrimal fossa on the superolateral part of each orbit; gland is divided by tendon of levator palpebrae into superior and inferior branch. (Secretion is stimulated by parasympathetic fibers of CN VII)lacrimal ducts drain the gland into the superior conjunctival sacs and are pushed across eye by the eyelids into the lacrimal lake in the medial angle of the eyelacrimal punctum and lacrimal canaliculi drain the lake into the lacrimal sac and finally into the nasolacrimal duct to drain into posterior nasal cavityEye –KNOW anatomy : cornea, pupil, iris, lens, ciliary body, suspensory ligament, canal of Schlemm, anterior and posterior chambers, aqueous humor, vitreous humor, sclera, fundus, choroid, retina, optic nerve, fovea centralis, blind spot (optic disc), central A&V, and retina Accommodation -focusing of images on retina (define: myopia, hyperopia,presbyopia)Retina -contains three basic zones of neurons plus a pigmented epithelium1. photoreceptor cells -specialized neurons able to perceive light (rods and cones) contain photopigments which react to light2. bipolar neurons -integrative area; lateral inhibition begins here3. ganglionic neurons -transmit signal to CNSOcular Movement –4 rectus muscles and 2 oblique (See Table 7.8 for AOI and innervation);the fascial sheaths of the muscles and optic nerve fuse to form a cup-like sheath around eyeballVascular Supply –mainly the ophthalmic artery (branch of internal carotid) and the infraorbital artery; most of the ophthalmic veins drain into the cavernous sinus or facial veinNasal Region –part of respiratory tract above palate and contains the olfactory areaExternal Nose –root, apex, nares, ala; formed from nasal bones and parts of maxilla and frontal bones, and nasal cartilages (2 alar, 2 lateral and one septal); the entire nasal septum also includes the perpendicular plate of the ethmoid and vomer bonesNasal Cavity –lined by mucosa except in the vestibule (thin skin with hair); air enters nares and exits through choanae into nasopharynx; the cavity is continous with the paranasal sinuses (frontal, ethmoid, maxillary and sphenoid sinues)Nasal Conchae –plate like extensions into nasal cavity to increase surface area and direct air flow; hydrate, warm and clean incoming air (divides nasal cavity into three meatus like tunnelsVascular Supply –by branches of internal carotid and facial artery (note: Kiesselbach’s area); venous drainage includes plexiNerve supply by Trigeminal Nerve branches (V1 & V2)Olfaction -located above superior nasal conchae in the cribiform plate-3 kinds of cells involved: basal cells, supporting cells, and olfactory cells-olfactory gland -mucus gland which washes the sensory cells-extremely sensitive to a wide variety of chemical substancesTemporal Region –from the temporal lines to the frontal bones and inferior to the mandibular angle; CN VII penetrates subcutaneous tissue just inferior to external acoustic meatus and runs through the parotid gland towards its major destinations in the faceTemporomandibular Joint (TMJ) –two synovial cavities separated by articular disc, stabilized by the lateral ligament of the articular capsule and the stylomandibular and sphenomandibular ligaments; loose articular capsule results in joint with elevation, depression, protrusion, retraction, and lateral movement capabilitiesBlood Supply –mainly the superficial temporal artery a branch of the external carotidEar –divided into external, middle and inner regionsOuter Ear:Consists of the auricle (pinna)-made of thin skin covering an elastic cartilage (helix, tragus, lobule and concha), auditory canal (note shape in adult, 2-3 cm long), and tympanic membrane (thin, oval transparent membrane) –vibrates in sympathy with sound waves(note: umbo, arm and lateral process)-Lymphatic drainage to the mastoid, parotid or superficial cervical lymph nodesFunctions to conduct and concentrate air vibrations (sound) resulting in the movement of the tympanic membrane (eardrum)Middle EarIncludes the tympanic cavity with the ear ossicles (malleus, incus, and stapes), Eustachian (auditory) tube, round and oval windows, stapedius and tensor tympanii muscles, also connects with mastoid air cells through the mastoid antrumAir filled space that houses the ear ossicles, maintains equal pressure across tympanic membrane through the Eustachian tubeOssicles amplify the eardrum vibrations and eventually vibrates the oval windowThe two tiny muscles help prevent high intensity from reaching the inner earInner Ear-consists of the bony and membranous labyrinth and each can be divided vestibular and cochlear components; innervated by CN VIII (vestibulocochlear n.)-The cochlea which contains perilymph and cochlear duct, the space superior to the cochlear duct is the scala vestibui; the space below is the scala typmpanii; these two channels connect near the apex of the cochlear duct through a narrow channel called the helicotremaThe cochlear duct: (note: Modiolus and spiral ganglion)Consists of outer and inner hair cells, the basilar, vestibular, and tectorial membrane and is filled with endolymphPressure waves produced by the movement of the stapes against the oval window can be transmitted through the vestibular membrane and basilar membrane to the scala tympaniiThis vibration produces slight movement of the basilar membrane and the inner hair cells which convert this motion into electrical signals sent, via the cochlear nerve to the auditory association areas of the brainThe basilar membrane is narrow and tight near the oval window and becomes wider and looser near the apex of the duct. High frequency sounds stimulate the narrower, tighter base of the membrane; lower frequency sounds stimulate the apex.Therefore, the pitch of the sound is perceived by brain understanding what section of the basilar membrane is vibrating the most. Loudness is transduced by the overall level of activity being produced by the duct.Vestibular labyrinth Two kinds of equilibrium: static and dynamicStatic Equilibrium is your sense of balance when not moving; that is, your body’s (particularly the head) with respect to the gravity of the earth.Consists of the bony vestibule containing the saccule and utricle with their macula which are made up of a patch of hair cells with their stereocilia embedded in the otolithic membrane (a gel-like mass) with otoliths stuck to its upper marginEach hair cell has its stereocilia arranged by size from shortest to longest with the last long hair much thicker than the rest; this stereocilium is known as a KinociliumAs the head changes its orientation, the heavy otoliths cause the matrix to slide toward the gravitational source and bend the hair cellsIn the upright position there is a constant rate of AP generation, when the hairs bend toward the kinocilium the rate increases, when bent away the AP decrease in frequencyDynamic Equilibrium is your sense of balance while moving-consists of the semicircular canals containing the semicircular ducts each with an enlargement (ampulla) that has an area of hairs cells called the crista ampullaris which similar to the macula have their hairs embedded in a gel called the cupulaOral Region –includes the mouth (oral cavity), tongue, jaws, teeth, palate, tonsils, salivary glands, and lipsOral Cavity (Mouth) -for ingestion, mastication and tasting of food; generates the food bolus-consists of thin skin overlying skeletal muscle and a mucosa membrane (made of stratified squamous and LP and a thin submucosa); divided into vestibule and oral cavity properLips and Cheeks –form the external border of the vestibule, control size and shape of orifice; and have similar structuresLips –extend from nose to the lateral nasolabial grooves, inferiorly to the labiomental groove; the skin transitions from keratinized stratified squamous to non-keratinized stratified squamous of the mucous membrane in the skin surrounding the orifice –this begins at the vermilion border and continues into the orifice in the red margin-the lips are attached to the gingiva by labial frenulumsGingiva (gums)-fibrous tissue and mucous membrane covering the alveolar process of the upper and lower jaw-blood supply through the labial arteries (branch of facial a.), sensory nerve by CN V (V2 & V3), lymph drainage trough the submandibular and submental lymph nodesTeeth -mechanical digestion (mastication)-Anatomy: crown, neck, root, root canal, apical foramen, enamel, dentin, cementum, periodontal ligament, pulp cavity; Read about teeth in book including primary and secondary dentitions.-blood supply by alveolar branches of maxillary a., lymph drainage to submandibular lymph nodes, alveolar nerves from V2 & V3Palate –forms superior border of oral cavity proper; participates in swallowing, divided into hard and soft palate and connected to mouth floor by the palatoglossal and palatopharyngeal arches; note incisive, greater palatine, and lesser palatine foramen and the nerves they carry; uvula is an extension of the soft palateTonsils -masses of lymphoid tissue embedded in mucous membranes; useful in surveillance functions; three present in this area: a pair of palatine tonsils sitting between the two arches, a lingual tonsil embedded in the root of the tongue, and a pharyngeal tonsil in the nasopharynxTongue -involved in mechanical digestion, swallowing (deglutition), taste, and speechanatomy: root, apex, body, lingual sulcus, lingual frenulum-4 kinds of papillae (which are peg-like projections of mucosa): 1. filiform –most numerous, conical shaped and keratinized, roughen tongue to increase friction; no taste buds 2. foliate –small lateral folds, taste buds present 3. fungiform -mushroom shaped; taste buds present, widely dispersed across tongue 4. vallate (circumvallate) –found in V-shaped row 2/3 back on tongue, all contain taste buds-rest of tongue in oropharynx and contains lingual tonsil;-highly muscular with both intrinsic and extrinsic muscles-Blood supplied by the lingual a. (branch of ext. carotid), lingual veins drain into IJV; lymph drainage from posterior half into sup. and deep cervical lymph nodes, the anterior drains into the submandibular and submental lymph nodes-Anterior 2/3 of tongue general sensation by V3 and taste by CN VII, posterior 1/3 both taste and general sensation by CN IX (glossopharyngeal n.) plus contributions from X; motor supply carried mostly by CN XII Taste -located in taste buds on tongue, soft palate, and throat-3 types of cells: basal, supporting, and gustatory cells; primary tastes are salt, sweat, bitter and sour; certain areas of the tongue are more sensitive to a particular primary taste; some specific chemicals can be detected (i.e. umani receptors detect amino acid (glutamate) of beef)Salivary glands –paired glands that secrete saliva; main glands are parotid, submandibular and sublingual -saliva –complex mixture of water (99%), electrolytes, mucus, enzyme and antibodies; primary role is to moisten mouth and food (some contain salivary amylase (breaks down starches))Parotid Gland –contained in parotid sheath (extension of neck fascia); wedged between mastoid and ramus of mandible; the parotid duct passes horizontally from the anterior edge of gland, pierces the buccinator and opens into the superior vestibule opposite the 2nd molar; secretion stimulated by parasympathetic fibers of CN IX (glossopharyngeal n.)Submandibular Gland –sits in a cervical triangle (submandibular triangle) just underneath the body of the mandible, the submandibular duct passes medially to empty through small openings at the base of the lingual frenulum, parasympathetic innervation by the CN VII (Facial n.)Sublingual Gland –smallest and deepest of the salivary glands, located in mouth floor just underneath the lingual frenulum, empties through several small ducts along sublingual folds. Innervation same as submandibular.Cranial FossaPRIVATE Protection of the brain: bones (skull) and meninges-meninges -CT coverings surrounding the CNS, support A&V, disperse and reabsorb CSFCerebral Spinal Fluid (CSF)-filtrate of the blood, bathes the CNS and fills cavitiesVentricular system: four ventricles (2 lateral, a 3rd and a 4th), interventricular foramen, cerebral aqueduct, median and lateral apertures, cisterns-CSF -produced by choroid plexuses within each ventricle (from modified ependymal cells)-eventually the CSF is reabsorbed to blood through the arachnoid granulations (villi); these small protrusions of the arachnoid through the meningeal layer of the dura into the dural sinuses (especially, superior sagittal sinus and lateral venous lacunae)1. Dura Mater (outermost) -tough, fibrous CTIn the brain –split into two sheets (meningeal and periosteal layers); the two are usually firmly attached together, but separate for large venous sinuses and to form reflections that help hold the brain in position (Cerebral falx, Cerebellar falx ,Tentorium, and Sellar diaphragm)-dural sinuses receive all the blood from the brain and some parts of face and ultimately empty into IJV (See book) know sinuses (straight, cavernous, superior and inferior sagittal, lateral venous lacunae, and sigmoid). Most of the blood drains into the IJV; in addition, emissary veins link the sinuses with external veins of the cranium.-Blood supply by several small cranial arteries and a large middle meningeal artery branching from the maxillary artery. (note: the middle meningeal A&V is found just under the pterion.) These arteries also supply the calvaria.-nerve supply mainly by the CN V, many pain receptors along blood vessel coursesIn the spinal cord –a continuation of the meningeal dura, remains unattached from the vertebra and separated by the epidural space (which is filled with fat and loose CT); the epidural space in the brain is only a potential space, since the periosteal layer is attached to the calvaria-potential space between the arachnoid and the dura => subdural space2. Arachnoid (middle) web-like appearance; the membrane is held up against the meningeal layer of the dura mater by CSF pressure and has many arachnoid trabeculae connecting it to the pia mater-space between arachnoid and pia => subarachnoid space3. Pia Mater (innermost) –thin transparent membrane attached to CNS, highly vascular (particularly with the arteries that supply the brain) Development:white matter -areas of the CNS with few cell bodies but many myelinated axonsgray matter -areas of the CNS with many cell bodies but few axons -starts as enlargement of ectoderm on back of embryo -the thickening soon folds to form a hollow tube -significance with spina bifida -the brain arises as enlargements from the cranial portion of the tubeBrain Anatomy: gyri, sulci, cerebrum, lobes of cerebrum, thalamus, midbrain-pons, cerebellum, arbor vitae, medulla oblongata, brain stem, pineal, diencephalon, corpus callosum, fornix, septum pellucidum, hypothalamus, intermediate mass -See Figures: Structures and functions of the brain.Blood supply: from internal carotid and vertebral arteries-internal carotids enter through the carotid canals and give rise to the anterior and middle cerebral arteries-the vertebral arteries begin at the subclavian a. and pass through the transverse foramen of the cervical vertebra and then through the foramen magnum; they then unite at caudal border of pons to form the basilar artery. The basilar a. gives rise to the posterior and anterior inferior cerebellar arteries, a number of smaller arteries feeding the brain stem, and end by dividing into the posterior cerebral arteries-a pair of small posterior communicating arteries connects the blood flow of the posterior cerebral a. with the internal carotid a.; likewise a small anterior communicating artery connects the right and left anterior cerebral arteries—creating the cerebral arterial circle (Circle of Willis)-venous drainage from both deep and superficial veins of the brain flow into the dural sinuses and then into the IJVEndocrine System –inside skullPRIVATE Characteristics: -controls and modifies the internal environment (primarily) by releasing chemicals into the blood (hormones)-endocrine glands secrete their products into the blood (not into ducts) -effects are slower in response time; but are usually longer lasting than the nervous systemPituitary(hypophysis): location -above the roof of the mouth; at the base of the thalamus; features: divided into: Anterior Lobe (adenohypophysis) -secretion controlled by releasing factors from the hypothalamus secreted into a portal system (hypothalamo-hypophyseal portal system) Posterior Lobe (neurohypophysis) -stores hormones produced by neurons in hypothalamus-long and short loop feedback mechanismsPineal: location -above the midbrain; thought to play role in regulation of body rhythmsTypes of Endocrine Disorders hyposecretion -too little secretion of hormone (primary or secondary) hypersecretin -too much hormone is secreted (primary or secondary) hyporesponsiveness -normal secretion, but little or no response of the target tissue Growth (as example of endocrine function)process influenced by genetics, endocrine function and environmental factors (nutrition and disease)-typically characterized by cell division and protein synthesis Bone growth: review anatomy of long bone: epiphysis, diaphysis, medullary cavity, epiphyseal plate, cartilage -cartilage of epiphyseal plate allows bone to lengthen and is eventually completely replaced by bone -2 major growth periods: Pre-pubertal (first 2 years) and puberty (sex differences) -to obtain genetic max, a person needs: adequate nutrition (protein, vit, FA, minerals, sufficient energy) and be relatively disease free (if sick for extended time most children can perform catch-up growth)-prenatal growth is largely independent of GH, T3 and sex hormones; however, these are very important for postnatal growthGH -secretion stimulated by exercise, fasting, decreased glucose, sleep, stress; pulsatile secretion (diurnal rhythm) -actions:1) stimulates differentiation of pre-cursor cells and secrete IGF-1 2) stimulates protein synthesis 3) anti-insulin effects : increase lipolysis and gluconeogenesis; inhibits glucose uptake -IGF-1 (somatomedin C) -secreted by the liver and many other cells acts locally to enhance the sensitivity of target tissues to itself and stimulates cell mitosis; and therefore growth. -understand GH secretion and feedback loops -affects of other hormones: T3 : essential and permissive for GHinsulin : essential and most dominant growth hormone for natal developmentSex horm: stimulates surge of GH at puberty, closes epiphyseal plates, anabolic (Test.)Cortisol: anti-growth (decrease cell division, increase catabolism)GH disorders: gigantism, acromegaly, dwarfismNeckBony structure: Cervical vertebra, hyoid, clavicles, scapulae (on posterior), and the manubrium of the sternumGeneral vertebra: Centrum (body), spinous process, transverse process, lamina, pedicle, vertebral (spinal) foramen, superior and inferior articulating surfaces, and intervertebral foramenCervical vertebra: (C1-C7), the typical vertebrae have short (usually bifid) spinous process, large triangular spinal canal (vertebral foramen), and a transverse foramen (carries vertebral vein and artery (artery not in C7): three are atypical: C1 (atlas), C2 (axis) and C7Spinal Cord:-16-18" long; -two enlargements (plexus): 1. cervical2. lumbar-consists of 31 segments each with a pair of spinal nerves: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal-the cord stops at the 1st-2nd lumbar vertebra -the remaining nerves pass down the spinal column as the caudal equina-Cross-section of Cordknow the following structures: roots of the spinal nerve, rootlets, and white columns, central canal, spinal nerve, posterior root ganglion, ventral and dorsal rami, rami communicantes, sympathetic chain ganglion and the arrangement of white and gray matter-ascending pathways -neuronal links which carry information up the cord -descending pathways -neuronal links which carry information down the cord; these are illustrated during facilitation of the patellar reflex arc during mental activity -reflex arch anatomy (simple)Hyoid –U-shaped, suspended at the C3 level by muscles connecting to the mandible, styloid process, manubrium, scapulae, and thyroid cartilage (Anatomy: body and greater and lesser horns (cornua)Fascia –divided into superficial and deep everywhere in body; superficial is same as the subcutaneous layer studied with skin. The deep usually is continuous with the fascia layers surrounding body muscles, but in neck divides into three distinct layers:Investing –extends from base of skull to the bones surrounding the root of the neck (note nuchal ligament); encapsulates the entire neck just below the superficial fasciaPretracheal –extends from hyoid into the neck merging with fibrous pericardium, wraps the infrahyoid muscle, trachea, thyroid and esophagus and extends posteriorly and superiorly into the pharynx as the buccopharyngeal fascia; also form CT rings that redirect digastric and omohyoid musclesPrevertebral –forms sheath surrounding the vertebral column and the muscles associated with it. Extends from base of skull to T3, laterally forms axillary sheath covering the brachial vessels and plexus.Alar Fascia and Carotid sheaths –CT surrounding Carotid a., Int. jugular, and vagus n. joined left to right by Alar fascia-these deep cervical fascia layers form natural cleavage planes (allowing separation during surgery), restrict the spread of abscesses, and allow movement of the structures in the neck past one another with little difficulty-Note: retropharyngeal space –allows movement neck organs against spine during swallowing; carotid sheath –extends from the base of skull into the root of the neck and contains: IJV, common and internal carotid a., CN X, some deep cervical lymph nodes nerves to carotid sinusSuperficial Muscles of the Neck: Platysma, SCM and TrapeziusTriangles of the Neck: Anterior and Posterior Triangles split by SCMPosterior Triangles: Occipital and Supraclavicular divided by omohyoid–bounded by sternocleidomastoid (SCM), trapezius, and middle portion of clavicle-visible within triangle are the accessory nerve (XI), trunks of brachial plexus, inferior belly of omohyoid muscle, external jugular vein and a small portion of subclavian A&V (the subclavian passes under the clavicle and runs over the first rib)-Deep muscles are the splenius capitis, levator scapulae, and the scalenes-receives venous drainage of lateral scalp and side of face-lymph drainage through superficial cervical lymph nodes located along EJV above SCM; these drain into deep cervical lymph nodes lying in carotid sheath-Nerve Point of the Neck –cutaneous branches of cervical plexus emerging around the middle of the SCM posterior borderCervical plexus –made from ventral rami of C1-C5 through a combination of nerve loops (two important nerves from the loops ansa cervicalis and phrenicAnterior Triangle –divided into 4 triangles –bounded by the SCM, the neck midline and the mandibleMuscular triangle –bounded by superior belly of omohyoid, anterior border of SCM, the hyoid and the midline of neck-contains the thyroid and parathyroid glands, the larynx as wells as the infrahyoid muscles (sternohyoid, sternothyroid, thyrohyoid, and cricohyoid muscles)Thyroid gland -left and right lobes, and isthmus (pyramidal lobe some time present);-blood supply through sup. and inf. thyroid A&V (branches of the external carotid and thyrocervical a.); (10% have thyroid IMA a.); venous drainage through the superior and middle thyroid veins into the IJV and the inferior thyroid vein into the brachiocephalic vein-lymph drainage to deep cervical lymph nodes; -nerve supply from cervical sympathetic plexi (for blood flow control)-gland has CT capsule that divides (by septa) the organ into lobules this fascia is continuous with the pretracheal fascia and anchors organ to cricoid cartilage and tracheal rings- derives from tissue at base of tongue (near foramen cecum) connected by duct to foramen initially (thyroglossal duct) which degenerates-produces thyroxine (T3 and T4) from the thyroid follicles which controls metabolic rate and is permissive for growth-stimulated by TSH from anterior pituitary gland-hyperthyroidism: Graves, exophthalmos, toxic goiters; hypothyroidism: (cretinism and myxedema), endemic goiters-also secretes calcitonin (lowers blood calcium –by stimulating bone deposition)Parathyroids glands found on posterior surface of thyroid lobes (maybe too small and diffuse to recognize), usually 4 in number; blood supply same as thyroid or supplemented by flows from esophagus, trachea, or larynx, venous flow same as thyroid-triggers an increase in blood calcium levels through action at four levels-increases bone resorption (increases Ca2+ and PO4- levels in blood)-increases skin production of vit. D-increases GI absorption of Ca2+-increases kidney Ca2+ reabsorption and decreases PO4- reabsorptionCalcium regulation-blood calcium levels are maintained at constant levels Importance: low calcium in blood may lead to skeletal muscle spasms (due to increased excitability of nerves and muscles) -high calcium levels may lead to cardiac arrhythmias and decreased neuromuscular excitability -these changes attributed to calcium's binding to ion channel proteins (opening and closing them)-the level of calcium depends on bone, kidneys, GI tract and a few endocrine glands (especially the thyroid and parathyroids)Bone: cellular structure: osteoblasts, osteocytes and osteoclasts, matrix, osteons, collagen, hydroxyapatite-99% of total body calcium is contained in bone; therefore, bone acts as a reservoir for calcium, inorganic phosphate, and other minerals, whether Ca++ is put in or removed (resorbed) from bone is under hormonal controlKidneys: -60% of blood Ca++ is filterable (the rest is bound to blood proteins), most of this is reabsorbed by the kidneys depending on the overall concentration of Ca++ in the blood; this control aspect is again modified by hormones.Also, the reabsorption of phosphate is also hormonally controlled and has an effect on Ca+ balance.GI tract: Normally more calcium is ingested than is absorbed by the GI tract, hormones control the extent of this absorption. Hormonal control:PTH -stimulated by decrease in plasma Ca++ actions: 1. increase resorption of bone and phosphate2. activates kidney enzymes which convert inactive Vit D3 into active VitD33. increases renal reabsorption of Ca++4. decreases renal reabsorption of phosphateVitamin D -can be formed in the skin the absorption of sunlight to convert 7-dehydrocholesterol into inactive plasma vitamin D3 and then converted by enzymes in liver to 25-OH D3 and finally in the kidneys to 1,25 (OH)2 D3-stimulates gut to increase Ca++ absorption-deficiency leads to Rickets (children) or osteomalacia (adults) leads to loss of mineralization in bone-osteoporosis -loss of mineral and matrix (most commonly associated with aging)Calcitonin -stimulates the mineralization of bone (decreases plasma Ca++) may not be very important in overall physiologyLarynx –thyroid cartilage with its laryngeal prominence, cricoid cartilage, arytenoids cartilages, epiglottis, thyrohyoid membrane, true (vocal fold)(vocalis muscle and vocal ligament) and false (vestibular fold) vocal cords-functions as valve (between esophagus, trachea and pharynx) and sound production -most laryngeal muscles innervated by recurrent laryngeal nerve (except the cricothryoid by external laryngeal n.)-sensory function to the larynx supplied by internal laryngeal n.-larynx grows steadily until 3 years of age, then little change until puberty; at puberty larynx strengthens and the vocal folds lengthen (esp. in males); with age the laryngeal cartilages may calcifySubmental triangle –bounded by the mandible, hyoid and anterior bellies of the diagastrics-contains the submental lymph nodes that run into deep cervical lymph nodes-venous drainage through the anterior jugular veinCarotid triangle –bounded by the superior belly of omohyoid, posterior belly of digastrics, and medial border of SCM-contains the carotid sheath which contains the common carotid artery, the vagus nerve and the internal jugular vein and the deep cervical lymphnodes; also within the triangle the hypoglossal nerve and ansa cervicalis can be found-the common carotid divides into internal and external carotids; bifurcates near superior border of the thyroid cartilage-the carotid sinus (enlargement of common carotid just inferior to bifuration) –responsible for baroreceptor reflex (sensory information relayed through glossopharyngeal and vagus nerves)-carotid bodies –red-brown masses on deep side of carotid sinuses, act as chemoreceptors monitoring pCO2, pO2 and H+ concentration in the blood –modify breathing-External carotid branches: maxillary, superficial temporal, superior thyroid, lingual, facial, occipital, posterior auricular, and ascending pharyngeal (some to cranial meninges)-Internal carotid goes into carotid canal in base of skull-this triangle drained by IJV; and is site of inferior bulb of IJV (large bicuspid valve in vein at root of neck) (the superior bulb is found at base of skull where the IJV emerges from the jugular foramen)Submandibular (Digastric) triangle –bounded by the anterior and posterior bellies of the diagastrics, and the mandible-nearly filled with submandibular gland and its duct which runs parallel to tongue-flanked by submandibular lymph nodes-hypoglossal nerve runs through this trianglePharynx - swallowing (deglutition) -junction area of oral and nasal cavities, esophagus and trachea-located posterior to nasal and oral cavities and extending inferiorly past larynx to the inferior border of the cricoid cartilage (C6) where it connects with the esophagus-contain inner longitudinal and outer circular muscles; innervated by pharyngeal plexus that is formed from branches of the vagus, glossopharyngeal and sympathetic branches of the superior cervical ganglion-divided into oropharynx, nasopharynx, and laryngopharynxNasopharynx –lies superior to soft palate and inferior to sphenoid and basilar part of occipital bone, provides airway connection from nasal cavity to oropharynx-contains the paired pharyngeal tonsils on its posterior wall (adenoids); note the fold of mucous membrane (salpingopharyngeal fold) covering the salpingopharyngeus muscle (opens Eustachian tube during swallowing); additional lymphoid tissue is found at base of Eustachian opening (tubal tonsils)-sensory innervation from CN V2Oropharynx –bounded by soft palate, root of the tongue and the palatoglossal and palatopharyngeal arches, ending at the superior border of the epiglottis-functions mainly in deglutition (swallowing) of food bolus: 3 stagesvoluntary movement of bolus into oropharynx by tongueinvoluntary; soft palate elevated to seal of nasopharynx; pharyngeal longitudinal muscles and infrahyoid muscles contract lifting the larynx and widening the pharynxinvoluntary; the three pharyngeal constrictors (sup., middle, and inf.) contract sequentially and squeeze the bolus into the esophagus. The trachea completes sealing off with the lowering of the epiglottis.Laryngopharynx –extends from superior border of epiglottis to the inferior border of the cricoid cartilage where it is continuous with the esophagus.-contains the piriform recess (a small depression found alongside of the laryngeal inlet (important due to potential for foreign objects lodging in this space and damaging the internal laryngeal or recurrent laryngeal nerves that lie deep to the mucous membrane of the recess)Thorax: Chest and PleuraSkeletal and Surface StructuresSurface Features:Anterior Median Line (AML) (midsternal) –intersection of median plane with anterior wallMidclavicular lines –parallel lines to AML passing through the midpoints of the claviclesMidaxillary line –bisects the apex (deepest part) of the axillary fossa and parallels the AMLPosterior Medain Line (PML) –intersection of median plane and posterior wall (runs along tips of spinous processes)Scapular lines –run parallel to PML and intersect inferior angles of scapulaeThoracic Vertebra (12) –review anatomy of typical vertebra; notice elongated spinous process of thoracic vertebra and sites for rib articulationRibs –(12 pairs) head with two facets, neck, tubercle, body, costal groove, costal cartilages(7 vertebrosternal (true), 3 vertebrochondral (false), 2 vertebral (floating and false)-note rib articulation with vertebra (most intervertebral)-1st rib is short and broad (widest and shortest rib; most curved), head has a single facet, and lies under clavicle (cannot be palpated), has a number of grooves on its surface to allow the passage of the subclavian vessels and part of the brachial plexus-note: intercostal spacesSternum –manubrium, jugular notch –trachea marker, sternal angle-marks 2nd rib, body (in young consist of sternebrae), and xiphoid processClavicle –delineates root of neck from superior thoracic aperture, and acromion joint forms point of shoulderScapula –3 borders, 2 angles, notch, acromion, coracoid process, spine, the rest will be studied with limbMiscellaneous -deltopectoral triangle –contains cephalic vein, and thoracic apertures (superior (inlet) and inferior ((anatomical) outlet))Breasts –normally only well developed in female, male breasts consist of only a few functionless ducts-develop as glandular and fibrous tissue embedded in a fatty matrix n the subcutaneous tissue of the chest over the pectoralis muscles; the amount of fat surrounding the glandular tissue determines the size of the breasts in non-lactating women-nipple in males associated with T4 dermatomeFemale Breast -nipple, areola, mammary gland, suspensory ligaments, lobes, lactiferous ducts and sinuses-extends from lateral border of sternum to midaxillary line and from the 2nd to the 6th rib-15-20 lactiferous ducts drain the lobes of the mammary tissue in a lactating breast, these tubes dilate into lactiferous sinuses just prior to exiting at the nipple-the nipples are cylindrical projections of skin in the center of the areola (lack hair, fat and sweat glands) with circular smooth muscle fibers surrounding the lactiferous sinuses; these muscles compress these ducts during lactation and erect the nipple in response to stimulationPolymastia (supernumerary breasts) or Polythelia (supernumerary nipples) may develop anywhere along the “milk” line; which extends from the axilla to the groin-the areola is an area of highly pigmented skin surrounding the nipple, it contains may large sebaceous glands (dimple the surface) which secrete an oily fluid to prevent chafing and cracking during beast feeding-a small part of the breast may extend toward the axilla –the (axillary) tail of (Spence) the breast (may enlarge slightly during a menstrual cycle –falsely alarming the woman)-between the breast and the pectoralis muscle is a potential space (retromammary space) which is partially filled with fat; allows some movement of the breast over the muscles-the breast is firmly attached to the skin and the pectoral fascia by suspensory ligaments (Cooper ligaments); which also support the gland’s lobules-vascular supply from branches of the internal thoracic, axillary, and intercostal arteries; venous drainage mostly through the axillary vein (some through the internal thoracic)-Lymph drainage: lymph from the nipples, areola and lobules drain into the subareolar lymphatic plexus then:75% (especially from lateral quadrants drain to the axillary lymph nodes)the medial quadrants drain into the parasternal nodesthe lower quadrants may pass into the inferior phrenic nodes-eventually the lymph is returned to circulation at the subclavian/jugular vein junction-nerve supply by the intercostal nerves (sensory to skin, sympathetic to breast blood vessels and nipple)Muscles of the ThoraxPectoralis Major –adducts arm, pectoral nervesPectoralis Minor –draws scapula forward, pectoral nervesInternal intercostals –expiration; depresses ribsExternal intercostals –inspiration; elevates ribsTransversus Thoracis –depresses ribsSerratus Anterior –abduction and raising of arm (pushing), long thoracic nerveDiaphragm -central tendon; aortic, IVC and esophageal hiatus; inspiration; phrenic nerveportions of scalenes, abdominals, and other back and shoulder musclesBreathing:- mainly by developing vacuum pressure by depressing the diaphragm and rotating the ribs up and out (produced by contraction of external intercostal muscles) (Additional chest muscles may play a role in more forceful breathing)- the expansion of the chest creates a drop in both intrapleural and intrapulmonary pressure below atmospheric pressure; the result is that air rushes down its pressure gradient into the lungs (Stretch receptors in lung and chest wall fire inhibitory signals to the medulla inspiratory center shutting down the inspiratory stimulus -the Hering-Breuer reflex) - punctures of lungs or body wall can adversely affect breathing; resulting in pneumothorax- normally expiration is a passive process; due to the elastic recoil of the lungs and chest and the relaxation of the inspiratory muscles the chest volume drops which creates a rise in lung pressure above atmospheric and the air rushes out- forced expiration (internal intercostals + abdominal muscles) can further increase lung pressure by as much as 20-30 mm HgNerves of Thoracic Wall-formed from the spinal nerves; dorsal rami supply the bones, skin and muscles of the back; ventral rami form the intercostal nerves; each connects to the sympathetic chain ganglion via white and gray communicating rami-understand dermatomes (skin segments) and myotomes (muscle segments)-Phrenic nerves (ventral rami of C3-C5); bilateralPleura CavitiesPleural membranes line the pleura cavities and are filled with serous fluidParietal pleura (diaphragmatic, cervical, costal, and mediastinal portions) with underlying endothoracic fascia (become thicker at pleura (cervical) cupula –the extension of the sup. lungs and pleurae into the sup. thoracic aperture)Visceral pleura –cardiac notch, costomediastinal and costodiaphragmatic recesses-each is continuous with each other at the root of the lungRespiratory Organs:- primarily concerned with external respiration (getting O2 to respiratory (resp) surface (membrane) for exchange with blood)- the upper resp. tract is above the pharynx, and the lower resp. tract is below the pharynx-the lower resp. tract is derived from evaginations of the pharynxLungs and their Ducts-develop as outgrowths of pharynx floor-most tetrapods: the right lung is larger than left (or has more lobes)Lobes: Superior and Inferior (middle on right lung), apex, 3 surfaces (costal, mediastinal, diaphragmatic) Note: cardiac notch and lingula.Fissures: oblique and horizontalTrachea, primary bronchiRoot of the Lung: hilum, secondary (lobar) bronchus, pulmonary artery and veins, pulmonary ligament, pulmonary lymph nodesDeep root of lung: segmental (tertiary) bronchi, bronchopulmonary segments (10 in each lung)Left Pleural Cavity: descending aorta, thoracic aorta, intercostal A&V, hemiazygous v., intercostal nerves, sympathetic trunk and gangliaRight Pleural Cavity: Sympathetic trunk, sympathetic chain ganglia, azygous v, intercostal A&V and nervesBlood Supply to Lungs-Pulmonary trunk to PA leads to lobar and segmental a. that parallel the bronchi, provide oxygen poor blood to the alveoli-pulmonary veins run intersegmentally draining adjacent segments merging into the 4 large pulmonary veins leading to the heart; receive flow from alveoli, visceral pleura and some bronchial blood flow-bronchial a. arise from thoracic aorta (usually) and provide blood to the bronchi, visceral pleura and other supportive tissues of the lungs, bronchial veins receive some of this blood flow and lead back to the hemiazygous and azygous veins (which receive additional blood flow from the intercostal v. and other regional blood flows)Nervous supply –from the pulmonary plexus which consists of parasympathetic and visceral sensation fibers from CN X and sympathetic fibers from the thoracic sympathetic trunks-parasympathetic fibers functionally are: bronchoconstrictor, vasodilator, secretomotor-sympathetic fibers functionally are: bronchodilator, vasoconstrictor, inhibit bronchial gland secretionConducting Air PassagesLarynx Trachea 1o Bronchi 2o (lobar) Bronchi 3o (segmental) Bronchi-3o Bronchi feed the bronchopulmonary segments which are separate from other such segments by CT and are therefore dissectible and is the largest subdivision of a lobe--airway divides a further 20-25x ending in terminal bronchioles - from nares to terminal bronchioles; conduct air to resp. membrane - also condition the air (filter, warm, and moisten); trap particles in mucous and cilia move this debris toward the pharynx; in addition, the mucous contributes moisture. (see lecture notes for more detail) -layers:1. Mucosa -epith. + BM (pseudostratified ciliated columnar)2. Submucosa - CT and mucous glands3. Cartilage -incomplete rings with smooth muscle (trachealis) completing the ring found in trachea and bronchi4. Adventitia - loose and elastic CTRespiratory Passages (which carry on diffusion) -respiratory bronchioles to the alveoli-respiratory bronchioles divides into 2-11 alveolar ducts which give rise to 5-6 alveolar sacs terminating in clusters of alveoli (300 million+)Alveoli: three layers1. epith. + BM:-type I pneumocytes - simple squamous cells function in exchange of gas-type II pneumocytes - produce surfactant (a lipoprotein) which reduces surface tension in alveoli (preventing their collapse2. CT - between alveoli; not involved in exchange of resp. gas3. Capillaries - endothelium + BM (BM for resp. and capillary fuse)- dust cells (macrophage) engulf particles lodged in alveoli- constitutes the thinnest diffusion membrane in body-Respiration is affected by body size, age, gender, and health status- lung capacities: tidal volume, residual volume, inspiratory reserve capacity, expiratory reserve capacity, vital capacity, total lung volumeControl of Respiratory Rate and Depth- rate and depth of breathing controlled by circulating levels of carbon dioxide and H+ concentrations (monitored in the aortic and carotid bodies and in the brain itself); high levels stimulate brain inspiratory center to trigger increased ventilation.- Also, low 02 concentration can be detected, but only functions when levels are extremely lowRelated Medical Significances:Pneumothorax – presence of air in pleural cavityAtelectasis (secondary) –collapse (decrease lung volume) of a previously inflated lung (primary is the failure of a lung to inflate at birth) -detectable by elevation of diaphragm and mediastinal shift toward the affected side, and the lung radiographically will become more dense (whiter) and the pleural space more translucent (blacker)Thoracentesis –penetration of the pleural cavity with a hypodermicPulmonary Embolism –blood clot blocking a pulmonary arteryMediastinum–cavity between the two pleural cavities (superior and inferior (inferior further subdivided by pericardium into anterior, middle, and posterior))Superior mediastinum –runs from the superior thoracic aperture to the sternal angle and T4-T5 intervertebral disc (a plane commonly referred to as the transverse thoracic plane); contains thymus gland, aortic arch and its branches, ligametum arteriosum, SVC, brachiocephalic veins, vagus n., phrenic n., left recurrent laryngeal n., parts of the trachea, thoracic duct and esophagus; (the anterior mediastinum is sometimes included with the superior since they are continuous with one another)Thymus gland –bi-lobed mass of lymphatic tissue which functions to produce plasma cells capable of fighting invading microbes; attains maximum size at puberty and then is replaced by fat and CT in the adult -location -ventral and above heart; produces hormones for maturation of T-cellsGreat vessels of superior mediastinum: Aortic arch with the base of the left common carotid, the left subclavian, the brachiocephalic trunk, pulmonary trunk and the SVC (note: ligamentum arteriosum)Nerves in superior mediastinum-Vagus –descends from carotid sheath to pass anterior to the root of the lungs-contributes to the cardiac, pulmonary, and esophageal plexi-note: location of left recurrent laryngeal n.-Phrenic –supplies sensory and motor innervation to diaphragm- passes posterior to root of lungViscera of Superior MediastinumTrachea –connects larynx to bronchi; located anterior to esophagus and bifurcates into primary bronchi at level of sternal angleEsophagus –connects pharynx to stomach, lies posterior to tracheaThoracic Duct –located to the left of the esophagus and deep to the aortic arch-largest lymphatic vessel of body, drains lymph from left side of body and the entire body below the diaphragm; empties at junction of subclavian and jugular veinsInferior mediastinum –runs from the transverse thoracic plane to the diaphragm; divided into three compartments (anterior, middle and posterior)Anterior mediastinum –smallest compartment of mediastinum and continuous with superior, consists mostly of loose CT, fat, and houses parts of the internal thoracic vessels (In children the inferior lobe of the thymus may reside in this space)Middle mediastinum –contains the heart with its ensheathing pericardium and the roots of the great vesselsPericardium and Pericardial Sinus (Cavity) –parietal and visceral layersLayers of the heart and pericardial cavity:1.Endocardium (inner most) -composed of epithelium lining (endothelium) (simple squamous), basement membrane and CT; continuous with endothelium of blood vessels; provides unbroken smooth surface for blood cells to glide against2.Myocardium - cardiac muscle arranged in whorls3.Epicardium - (visceral serous pericardium) - composed of an epithelium surface, (mesothelium), basement membrane and CT; this layer is continuous with the parietal serous pericardium4.Pericardial Cavity - potential space with some fluid present, prevents friction on the heart5.Parietal Pericardium (pericardial sac) -the sac is the source of lubricating fluid in pericardial cavity; composed of two layers:-parietal serous pericardium -mesothelium ((+BM)-fibrous pericardium -CT that helps prevent over distention of the heart, bound to the central tendon of the diaphragm, to the sternum by small ligaments, and the tunica adventitia of the great vesselsTransverse Pericardial Sinus – space behind (posterior) aorta and pulmonary trunk ad anterior to SVC (site of coronary bypass machine insertion)Oblique Pericardial Sinus –blind sac formed by the growth of the great cardiac veins (IVC, SVC, and pulmonary veins)Pericardium supplied by branches of Internal thoracic, thoracic aorta and coronary vessels, drains mostly into the internal thoracic and azygous veins; nervous supply through the phrenic (sensory), Sympathetic trunks (vasomotor), and vagus (uncertain function)Development of Heart:-develop from mesoderm -the human heart begins pumping fluid at day 23 starts off as a single tubular structure which receives blood caudally and pumps it cranially to the ventral aorta-the tube twists to the anatomical right into an S-shape; moving the atrium more cephalad and dorsal-the twisting continues until the atrium lies cephalad to the ventricles; the atrium then enlarges forming two chambers divided by a septum-the ventricle splits and forms an interventricular septumFetal circulation -Know variations in adult-specialized structures for respiratory and nutrient exchange for the fetal environment-anatomy: placenta, umbilicus, umbilical a&v, ductus venosus, foramen ovale, ductus arteriosusHeart: Cardiac Muscle:-has sarcomeres; therefore, striations; the thin and thick filaments have the same arrangement as in skeletal muscle, sarcoplasmic reticulum is well developed and plays the same role as in skeletal muscle-the cells are short, branched uninucleated and joined to the next cell by intercalated discs (areas of interdigitation with many gap junctions); thus atria and ventricles act as a single unit-their depolarization differs from normal action potentials; the uplimb is due to Na+ permeability increase, the down limb is due to K+ flow; but these are separated by a plateau region due to the movement of Ca++ into the cell-this type of depolarization increases the refractory period for the muscle (which lasts about as long as contraction) and prevents cardiac muscles from summating their contractions-depolarization releases Ca++ from the SR (allowing contraction); additionally Ca++ enters through the cell membrane. Unlike skeletal muscle in response to depolarization, cardiac cells do not release enough Ca++ to completely saturate the troponin binding sites. Therefore, any event which would increase the cytosolic Ca++ increases the rate and force of contractionNa+Ca++K+Cardiac Muscle Cell Action PotentialGeneral Features:Size: -in humans, same as closed fist; 12cm long, 9 cm wide, 6 cm thick; located in the middle of the mediastinum within the pericardial cavityOverview of Heart Anatomy and the Flow of Blood Key anatomical terms: atria, ventricles, interatrial septum, interventricular septum (membranous ad muscular), apex, AV and semilunar valves, papillary muscles, chordae tendinae, ascending aorta, superior vena cava, left vagus nerve and the recurrent laryngeal nerve, ligamentum arteriosum, pulmonary trunk, inferior vena cava, pulmonary veinsExternal heart anatomy: right ventricle, right atrium, left ventricle, left atrium, apex, coronary sulcus, interventricular sulcus, auricles -atria receive blood and the ventricles eject bloodRight atrium: Pectinate muscles, fossa ovalis, right auricle, interatrial septum, and openings of SVC, IVC and coronary sinus. Note location of SA node and AV node-receives blood from the Vena Cava (blood from systemic circulation) and from the coronary (heart) circulation-blood passes to the right ventricle by flowing through the right AV valve (tricuspid)Right atrioventricular (AV) valve (tricuspid) – 3 cusps, chordae tendinae connecting to papillary muscles in ventricle, (auscultated at level of the left 4th intercostal space near sternum)Right ventricle: papillary muscles, moderator band, trabecula carnae, interventicular septum, pulmonary semilunar valve (3 cusps) opening of pulmonary trunk, auscultated at level of left 3rd intercostal space near sternum)-ejects blood to the pulmonary artery (lungs); passing the pulmonary semilunar valve-the blood flows through the lungs and returns via the pulmonary veins to the left atriumLeft atrium: pectinate muscles, auricle, openings for the pulmonary veins-receives the pulmonary veins and passes blood through the left AV valve (bicuspid or mitral) to the left ventricleLeft AV valve (bicsupid or mitral) –2 cusps, chordae tendinae, (auscultated at level of the left 5th intercostal space near distal end of rib)Left ventricle: trabecula carnae, papillary muscles. (Note thicker wall of this ventricle.) opening for aorta, aortic semilunar valves (auscultated at level of the right 3rd intercostal space near sternum), cusps, (In ascending aorta, aortic sinus and openings for right and left coronary arteries)-ejects blood to the aorta; passing through the aortic semilunar valve; the blood flows to all parts of the body and returns via the Vena CavaCoronary Circulation:-the heart must be supplied with its own set of vessels to get nutrients and oxygen (no exchange takes place between the blood flowing through the chambers of the heart and the cardiac tissues)-the coronary arteries arise out of the aortic sinuses just behind the semilunar valves; the coronary veins drain the blood into a small cavity at the rear of the heart called the coronary sinus which drains into the right atriumLeft Coronary artery: Left anterior descending (LAD) artery and the Circumflex arteryRight Coronary artery: Right marginal artery and the Posterior Descending arteryCoronary Veins: Small cardiac vein, Middle cardiac (posterior interventricular) vein, Great cardiac (anterior interventricular) vein, coronary sinus -Lymphatic drainage -lymph from the heart passes into the subepicardial plexus and empty into vessels traveling along the coronary sulcus which merge into a single vessel ascends between the pulmonary trunk and LA to empty into the tracheobronchial lymph nodesMajor Valves:-each valve is a nonmuscular flap of dense CT covered by endocardium designed to be a one way door to prevent the back flow of blood; the chordae tendinae and papillary muscles prevent valve regurgitation during peak systole-attached at base to a supporting ring of dense CT; the rings of all four valves merge and form a central core of CT that dives into the interventricular septum forming the fibrous skeleton of the heart (provide attachments sites for valve cusps, the myocardium, maintain the orifice of the valves patent and form an electrical insulator between atria and ventricles1.Atrioventricular (AV valves - tricuspid (rt.) and bicuspid (left) (mitral); open when ventricular pressure < atrial pressure and close when vent. press. > atrial press.-chordae tendinae attach papillary muscles to edges of valves to prevent rupture of the valves during systole2.Semilunar (SL) valves - aortic and pulmonary SL valves; consist of three “half moon” shaped cusps that seam together at a process called the corpora aranti; open when vent. press. > arterial press. and closed when arterial press. > vent. press.-minor valves include: the coronary sinus valve (Thebesian) and IVC valve (Eustachian)Nervous Control:-most cardiac muscle cells will spontaneously depolarize, but there are specialized regions which have a very regular and quick depolarization rate; these make up the conducting system of the heart: SA node, AV node, AV bundle (His), right and left bundle branches, and subendocardial branches (Purkinje fibers) -the Autonomic Nervous System regulates cardiac function by affecting these regions; sympathetic (secreting norepinephrine) from the thoracic sympathetic trunks -accelerate the heart rate and increases the force of contraction; and the parasympathetic (secreting acetylcholine) from the vagus nerve -decelerates the heart rate only-the ANS also modify the blood flow through the coronary circulation (P –constriction; S –dilation (for β receptors; constriction for α receptors)-these systems primarily innervate the sinoatrial node (SA) region (anterior to the SVC entrance in RA) and atrioventricular (AV) node ( in interatrial septum near entrance of coronary sinus); but send additional fibers to other portions of the conducting system and the sympathetic sends fibers directly to the myocardial contractile cells-the conducting system of the heart is composed of specialized cardiac muscle cells which have lost the ability to contract, but can initiate and conduct action potentials-The cardiac centers in the medulla coordinate ANS functioningFast Ca++ channels allow Ca++ inK+ channels openPacemaker PotentialsSlow movement of Na+ and Ca++ inward through normal leakage, with diminishing K+ conductance outwardOrder of Conduction1.Sinoatrial (SA) node - "pacemaker") generates regular electrical impulses (pacemaker potential); located in right atrium anterior to superior vena cava; the generation of action potentials here is faster than any other area of the heart2.impulse conducted by myocardium across atria through gap junctions; there are some preferred pathways known as internodal fibers3.Atrioventricular (AV) node - located in interatrial septum near coronary sinus; signals from SA node delayed (0.1 s) here to allow for nearly complete contraction of the atria before the ventricles; the delay is due to the slower depolarization of the AV node-NOTE: AV node can generate its own electrical signal if the SA node is damaged; in addition, problems with the AV node may lead to uncoordinated heart beats4.AV bundle (bundle of His) - conducts signal from AV node to ventricles, the ventricles are electrically insulated from the atria by fat and CT (fibrous skeleton of the heart); therefore, the Bundle of His and the AV node are needed to link atrial and ventricular contraction5.Right and Left Bundle branches - conduct signal to apex of heart and distribute it to the Purkinje fibers6.Purkinje fibers - distribute depolarization wave to the contractile myocardium (distributed to papillary muscles and interventricular septum first, the apex and then the outer walls of heart)Posterior Mediastiumthoracic aorta, esophagus, esophageal plexus, thoracic duct, azygous and hemiazygous veins, Thoracic sympathetic trunks, lymph nodesEsophagus - transports food to stomach (deglutition) Function: actively transports food via peristalsis-normally collapsed when food not present; has two sphincters upper and lower esophageal sphincters (lower is physiological only)Histology 1. Outer adventitia layer (CT); no mesentery 2. muscular coat contains smooth and skeletal muscle (gradient of skeletal to smooth muscle) 3. epithelium -stratified squamous with numerous mucus glandsNervous control by esophageal plexus, blood from esophageal arteries from thoracic aortaBlood liquid connective tissue; arises from hemopoietic (blood generating) tissue which consists of two types:1. Myeloid -red bone marrow, generates red and white blood cells2. Lymphoid -spleen, tonsils, thymus, lymph nodes, etc.; matures whites blood cells-in the fetus to early infant also have a the liver and yolk sac involved in producing blood cells-basic properties of blood:volume -4-6 L (5-6 for men, 4-5 for women); 8% of total body weightpH - 7.4 (ranging from 7.3 to 7.5); five times the viscosity of water;hematocrit: 45 (approx. volume of RBC in blood)-composition: (2 parts)1. Formed elements -cells (45% of the blood) (~hematocrit)2. Plasma -(55% of the blood) composed of 90% water and 10% suspended or dissolved constituentsPlasma constituents (10%):-0.85-0.9 M NaCl + other electrolytes and nutrients-plasma proteins -albumin, globulin, and fibrinogen-dissolved gases N2, O2, and CO2-functions of the blood:1. Transport media, 2. Acid-Base Balance -buffer systems,3. Osmoregulation -water-electrolyte balance,4. Protection -immunity-Hemopoiesis:-rate controlled by erythropoietin (hormone from kidney)-also regulated by availability of Fe++, folic acid, vitamin B12 and amino acid precursorsFormed Elements:I. Erythrocytes (RBC) -4.5-5.5 million/mm3 (mcl); lives 120 days-mature RBC is a non-nucleated biconcave disc; 7.5 mcm in dia. and 2 mcm in thicknessFunction: -transport of respiratory gases through the reactions of hemoglobin (RBC cytoplasm is 1/3 hemoglobin)hemoglobin: -four globulin proteins each with an associated heme group in the center (heme is a 20 carbon polypeptide with Fe++ at its center which binds O2 and CO2)II.Leukocytes (WBC) - 5-9 thousand/mm3 A.Granulocytes -granules in cytoplasm (lysosomes or vesicles)(polymorphonuclear [PMN] leukocytes -refers to their odd shaped nuclei); all have some degree of phagocytic abilityNeutrophils (55-65% of WBC) -phagocytic for bacteria and cellular debris-first to arrive at infection sites -its lysosomes contain acid phosphotase, hydrolytic enzymes plus antibacterial enzymes (defensins) which attack bacterila cell walls; also contain chemotaxic compounds (these attract other immune cells to site)Eosinophils (2-4% of WBC) -combat irritants that cause inflammatory response-destroy parasitic worm infections and readily engulf Ag-Ab complexes-lysosomes contain histaminase (anti-histamine) and hydrolytic enzymes-limit inflammatory responseBasophils (0.5% of WBC) -increase inflammatory response-lysosomes contain histamine, heparin and other vasoactive compounds which promote the flow of defenses to site of infection B.Agranulocytes 1. Monocytes (3-8% of the WBC) (macrophage) -phagocytic; second wave after neutrophils; most active when in the tissues; can move through BV wall and tissues without destroying its integrity called diapedesis (neutrophils have this same ability); strongly chemotaxic 2. Lymphocytes (20-25% of the WBC) "immune cells" B-cells: -produce Ab against the Ag T-cells: -different subtypes: helper, suppressers, and killer cells; control immune responseIII. Platelets (Thrombocytes) (150-400 thousand/mm3) -2-4 mcm in dia., no nucleus (cell fragments)-viable for 5-9 days; shed from megakaryocytes-aggregate at site of injury forming a plug which stops bleeding; in addition they secrete vasoconstrictors (i.e. serotonin), factors to activate fibrin (PF3), and platelet-derived growth factors (PDGF) [which stimulate the growth of the endothelium]Bleeding and CoagulationBleeding Time – the time it takes for a small wound to stop bleeding; uses extra-vascular and vascular mechanisms (tightening of skin and muscle, vasoconstriction and formation of platelet plug) Abdominal RegionPeritoneal Cavity –includes abdominal and pelvic cavitieslined with the peritoneum (visceral –on organs; parietal –on inner wall) with small amount of peritoneal fluidorgans within the cavity are suspended (intraperitoneal) or lie behind the parietal peritoneum in a retroperitoneal (extraperitoneal) positionextends from diaphragm (partially covered by lower thoracic rib cage) to the perineumumbilicus –prominent surface feature marking the consolidated scar of the umbilical cordAbdominal Regions and Quadrants-can be divided into 9 regions by four planes: (see diagram for names and location of viscera)2 horizontal: subcostal plane (passes through the inferior border of 10th costal cartilage) and transtubercular plane (passes through the iliac tubercles)2 vertical: midclavicular planes (passing through the midpoint of the clavicles and the anterior superior iliac spines-can also be divided into 4 quadrants defined by the transumbilical plane and the median plane-see book for list of viscera found in each quadrantAbdominal Wall –skin, fascia, muscle, aponeurotic tendons, and parietal peritoneum-the skin attaches loosely to the underlying muscles except at the umbilicus -the superficial fascia of the inferior part of the abdominal wall divides into two layers: Camper’s fascia (a fatty layer continuous with superficial fascia elsewhere, but can be extremely thick) and a Scrapa’s fascia (a membranous layer that fades out at the thorax and back, passes down to the inguinal ligament and passes over the pubis to form a sheath for the penis or clitoris, runs through the scrotum (or labia majora) and unites at the perineal bodyMuscles-three sheet like muscles with a broad tendon anteriorly (aponeurosis)external oblique –fiber run inferior-medially; a triangular shaped defect in the external oblique aponeurosis lies immediately above and medial to the pubic tubercle; known as the superficial inguinal ring (provides passage for spermatic cord in male). Between the pubic tubercle and the anterior superior iliac spine the lower border of this aponeurosis folds back upon itself forming the inguinal ligamentinternal oblique –fiber run superior-mediallytransversus abdominus –fibers run almost horizontally-the broad aponeurosis encapsulate a paired vertical muscle on either side of the midline; the rectus abdominus, thus forming the rectus sheath-the fibers of each aponeurosis interlace at the midline; this small indented line is the linea alba-the rectus abdominus run vertically in between tendinosus intersections-a small pyramidalis muscle may be present at the bottom of the rectus sheath-deep to the muscles, most of the abdominal wall is covered by the transversalis fascia, between this fascia and the parietal peritoneum lies the variable extraperitoneal (extrabdominal) fat pad-functions:strong flexible support of abdominal wallprotect and contain abdominal visceracontrol of compression of abdominal cavitymove the trunkNerve supply by ventral rami of spinal nerves T7-L1Blood supply:superior epigastrics and musculophrenic vessels from internal thoracic arteries supply upper abdominal wall and diaphragminferior epigastrics and deep circumflex from external iliacs supplies lower abdominal wallposterior intercostals and lumbar arteries from the aorta supply the dorsal abdominal wallsuperficial circumflex and superficial epigastrics from femoral supply skin of abdomenVenous drainage of abdominal wall flows through the same name vessels as described above except for the skin; drainage of the skin follows the following:Drainage of venous flow above umbilicus to lateral thoracic vein to axillaryDrainage below umbilicus mostly through inferior epigastrics to external iliac veinsparaumbilical veins connect to the hepatic portal vein through the umbilicus and ligamentum teres (round ligament) (an important portal-systemic anastomoses (–caput medusae))Lymphaticssuperficial drainage superior to umbilicus drainage to the axillary lymph nodessuperficial drainage inferior to umbilicus drainage primarily to the superficial inguinal lymph nodeslymph drainage within the cavity will be discussed with the visceraAbdominal CavityMesenteries –a double layer of peritoneum extending from the body wall to a organ, it will contain a core of CT, blood vessels, lymph vessels and nodes, nerves and fat. The suspension of organs by mesenteries allow organs some mobility.Peritoneal ligaments – are similar to mesenteries but or usually more limited or a subdivision of a mesenteryAbdominal Mesenteries and LigamentsFalciform ligament –connects anterior median portion of liver to diaphragm and ventral body wall (round ligament (teres ligament) remnant of umbilical vein)Greater Omentum –large sac-like membrane connecting the greater curvature of stomach to the transverse colonLesser Omentum –mesentery connecting the lesser curvature of stomach and proximal duodenum to the liver (divided into gastrohepatic (wide thin membrane) and hepatoduodenal ligaments (along lateral border of mesentery contains portal triad)-These mesenteries divide the abdominal cavity into the greater and lesser (omental bursa) sac; connection between these two sacs is through the epiploic foramen (omental foramen or foramen of Winslow); The greater sac is divided by the transverse mesocolon into the supracolic and infracolic compartment.Gastrosplenic ligament –extension of greater omentum (greater curvature to spleen)Transverse and sigmoid mesocolon –dorsal body wall to colonThe Mesentery –attaches bulk of small intestine to dorsal wallMedian umbilical ligament (urachus) –fundus of bladder to ventral wallMedial umbilical ligaments –remnants of umbilical arteriesDigestion (overview) - reduction through hydrolysis of complex food substances into simpler monomers Functions of digestive system:1. Motilityingestion -intake of food into GI tracttransportation of food through system by peristalsismastication -chewingdeglutition -swallowingmixing by segmentation and churningegestion -defecationSecretionexocrine: secretion of products to aid in digestion; like: HCl, water, bicarbonate, enzymesendocrine: secretion of hormones to regulate GI tractDigestion - mechanical (includes grinding, mixing, liquefying) and chemical breakdown of food into small particlesAbsorption - passage of particles from external to internal environmentMajor Organs (alimentary canal or GI tract)- mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, and anusAccessory organs-teeth, tongue, salivary glands, liver, gall bladder, and pancreasDevelopment: -primitive gut (archenteron) forms during gastrulation as the embryo folds into a cylindrical shape and encloses a tubular portion of the yolk sac, the tube consists of endoderm wrapped by splanchnic mesoderm -endoderm forms the epithelial lining of gut and glands -splanchnic mesoderm forms smooth muscle and CT of tube and organs -divided into foregut and hindgut separated by a constriction in gut tube (pylorus) Postgastrula development:-Stomodeum -invagination of ectoderm to form mouth which breaks through to connect with the pharynx; forming the oral cavity-Proctodeum -invagination of ectoderm which breaks through to the colon; forming the rectum and anusBasic histological pattern of generalized digestive tube: all organs of the GI tract have the same four basic layers with some modifications1. Mucosa: inner most, functional layer; has three sub-layersepithelium –responsible for absorption and secretion, lines entire tract, tubes of glands and secretory cells of glands are derived from it. Usually simple columnar in most areaslamina propria (LP) –loose areolar CT, furnishes blood and lymph vessels to epithelium; houses GALT (gut associated lymphoid tissue or MALT (mucosa-associated lymphoid tissue) first line of defense in gut–the epithelium and LP may be folded to form villimuscularis mucosa -smooth muscle layer that produces local movement of mucosa2. Submucosa –mixture of loose areolar and dense irregular CT, containing blood and lymph vessels, nerves, glands, and high amounts of elastin fibers-contains the submucosa nerve plexus (Meissner’s plexus) which controls gland activity and muscularis mucosa3. Muscularis (externa) –thick smooth muscle layer; usually consists of an outer longitudinal and inner circular layer (LOCI)-responsible for propulsion of food through lumen (peristalsis) and mixing (churning and segmentation contractions)-some areas the circular muscle layer enlarges to form sphincter muscles-myenteric nerve plexus (Auerbach’s plexus) lies between the two muscle layers and controls their activity4. Serosa (visceral peritoneum) –outermost layer; mesothelium with a small amount of areolar CT-in areas where the gut lies outside of the peritoneum, this layer is replaced by fibrous CT and is called an adventitia layerEnteric Nervous System-activity of the GI tract is controlled largely by neurons intrinsic to the GI tract with the autonomic nervous system only increasing or decreasing that activity-parasympathetic innervation provided by the vagus trunk or pelvic splanchnic nerves from the sacral spinal cord; sympathetic innervation from sympathetic trunk from the lower thoracic and lumbar regions (many through the celiac or superior and inferior mesenteric ganglia)Supracolic Compartment: contains the distal esophagus, stomach, liver, gall bladder, and spleen (duodenum and pancreas lie retroperitoneal but the pancreas will be described here)-blood supplied by aorta and venous drainage through the hepatic portal system in most casesStomach: - J-shaped muscular pouch which receives bolus and delivers chyme (liquefies food)Function - food storage and mechanical digestion (with some chemical)–used to temporarily store food and continue digestion (churns and liquefies food using HCl acid into a creamy paste known as chyme and begins enzymatic breakdown of proteins)–the stomach carries out little absorption except for water, electrolytes and some drugs (alcohol and aspirin, for example)Anatomy - cardiac, body, fundus, pyloric sections; rugae present (temporary foldings in mucosa layer)Histology same as basic pattern except:-muscularis has three muscle layers: outer longitudinal, middle circular and inner oblique–mucosa can form rugae -temporary longitudinal foldings that allow stomach expansion-simple columnar epithelium with openings leading to the gastric glands (pits) -Gastric glands may contain:1. mucous neck cells (a type of goblet cell) –secrete heavy mucus2. peptic (chief or zymogenic) cells –secrete pepsinogen (inactive enzyme that activates in acid to pepsin which breaks down proteins to polypeptides)3. parietal cells – secrete HCl and gastric intrinsic factor (protein necessary for vit. B12 absorption in intestine4. enteroendocrine cells –gastrin (hormone stimulates gastric juice production)5. undifferentiated stem cells –mitotically active cells which replace lost epithelial cells-gastric arteries arise from branches of celiac a., and drained into gastric v. into portal vessels-lymphatic drainage follows the arterial pathways towards the curvatures to the gastric and gastro-omental lymph nodes; then to the celiac lymph nodesSpleen -largest mass of lymphoid tissue in the body -about 12 cm long and 7 cm wide; fist size -surrounded by capsule composed of elastic CT and myoepithelial cells -composed of white pulp (lymphoid tissue) and red pulp (venous sinuses) -it rids the blood of cellular debris and bacteria (filters blood); blood is delivered by the splenic artery (from celiac) and emptied by splenic vein which unites with SMV to form the portal vein -it stores blood in its sinuses until needed; it can then decrease in size (owing to its elastic, myoepithelial capsule) via sympathetic stimulation to empty blood into the systemic circulation -it stores platelets and iron -it is a site of RBC production in the fetusAdrenals: location-above the kidneys; features -divided into cortex (with 3 zones) and medulla secreting different hormones, supplied by adrenal arteries from aorta-general adaptation syndrome (GAS) -the bodies reaction to stressPancreas-lies retroperitoneal, along the posterior abdominal wall between duodenum and spleen-head (and uncinate process), neck, body and tail-pancreatic duct and accessory pancreatic duct-lymphatic drainage via pancreatosplenic and pyloric nodes into the superior mesenteric nodes-heterocrine gland - both exocrine and endocrine - exocrine function: production of pancreatic juice from pancreatic acini (cells) into ducts-juice is sodium bicarbonate (buffer), water and digestive enzymes (trypsinogen, lipase, etc.)- endocrine function: secretes hormones into blood to regulate blood sugar levels- Islets of Langerhans (cells found in clusters between the acini)alpha cells - glucagon; beta cells - insulin; delta cells – somatostatinLiver -developed from outpocket of endoderm (hindgut); largest gland in body (second largest organ)Functions (over 500 known):metabolism of all three basic food typesstorage of Fe and Cu and glycogenstorage of Vit. A, B12, D, E, and Kproduction of plasma proteins (albumin, clotting factors, heparin, etc.)bile production (aids digestion by emulsifying fats in intestine)detoxifies the blood and can store toxinsAnatomy: gross anatomy: lobes (right, left, caudate and quadrate), porta hepatis (a transverse fissure which contains the portal vein, hepatic artery, and hepatic ducts plus nerves and lymphatic vessels); held by coronal lig., falciform lig., round lig., and the lesser omentum Internal anatomy:-the portal veins and hepatic arteries divide the liver into 8 vascular segments with the hepatic veins positioned intersegmentally- divided into lobules arranged in a hexagonal shape- hepatic portal venule (from portal system) and hepatic artery empties into sinusoids, which are bounded by hepatocytes produce bile into the bile canaliculi; the sinusoid then empties into the central vein which flow to form the hepatic vein that then communicate to the inferior vena cava-Kupffer cells –resident macrophage found in sinusoids; eliminate foreign matter and dying blood cells-bile canaliculi pick up bile produced by hepatocytes and moves it to hepatic ducts-the right and left hepatic ducts exit the liver unite with the cystic duct to form the common bile duct that enters the duodenum-in the duodenal wall, the common bile and pancreatic ducts merge in a papilla known as the Ampulla of Vater (major duodenal papilla) which empties the secretions into the duodenal lumen, control of this flow is managed by a small sphincter muscle near the Ampulla’s opening known as the Sphincter of Oddi (hepatopancreatic sphincter)-produces 25-50% of the lymph flow of the thoracic ductGall Bladder - develops from ducts of liverfunction: temporary storage and concentration of bile (holds up to 50 ml of bile)- simple columnar epithelium and no submucosa; rugae present-fundus, body, and neck (with spiral valve)-drained by the cystic duct into the common bile duct-with the Sphincter of Oddi or hepatic duct sphincter closed bile backs up the cystic duct and fills the gall bladder-the cystic artery arises from right hepatic artery (variations common), venous drainage joins portal flowInfracolic Compartment: contains small intestine, colon, appendix, kidneys, adrenalsSmall Intestine (Gross anatomy: duodenum, jejunum, ileum)–site of most chemical digestion and virtually all absorption, longest part of GI tract- site of largest amount of digestion and absorption-absorbs most of the nutrients in the chyme in about 4 hours and also about 7-9L of water which was originally added to food by GI tract- structures to increase surface area1. plica circularis - permanent foldings of the mucosa and submucosa2. villi - finger-like protrusions of the mucosa (epithelium and lamina propria) contains BV and lacteal3. microvilli - microscopic protrusions of the cell membrane from each epithelial cell creates an undisturbed brush border with embedded enzymes (ex. Enterokinase)4. increase length - the small intestine is the longest segment of the digestive tract (2 m in life; 6 m in cadavers)- mucosa has pits = crypts of Lieberkuhn (intestinal glands) which secrete intestinal juice; each gland contains the following cells:1. absorptive cells -columnar cells with digestive enzymes in their membranes2. goblet cells -mucus3. Paneth cells – enzymes which control flora and fauna of intestine4. enteroendocrine cells -hormones (secretin, CCK, etc.) controlling GI tract activity 5. stem cells -reserve cells, mitotically activeHistology same as basic patternDuodenum –C-shaped, starts at pylorus and ends at duodenojejunal junction. Receives acidic chyme of stomach and neutralizes it, and bile and pancreatic secretions through major duodenal papilla.-Brunner's glands - large mucus glands found in the submucous of duodenum; neutralize acid from stomach-blood supplied by the celiac to the proximal portions and the SMA to the distal portions-lymphatic vessels follow the arteries into either the pancreaticoduodenal, superior mesenteric, or celiac lymph nodes that drain into the thoracic ductJejunum and Ileum (6-7 m long) (jejunum: first 2/5; ileum last 3/5; the jejuum located mostly in the left upper quadrant and the ileum in the right lower quadrant) -blood supplied by SMA branches and drained by SMV into the portal vein-lymphatics drain into the superior mesenteric or ileocolic lymph nodes-Peyer’s patches –large lymphoid aggregates found in ileumLarge Intestine (2-3" in dia. and 3-5 ft. (~1.5 m) in length in life)Anatomy: cecum, appendix, ascending, transverse, descending colon, sigmoid, rectum, anal canal, flexures, semilunar foldsFunctions:- absorption of water and electrolytes; receives 1.5-2L of water a day and absorbs 90% of it; less than 200ml of water excreted with feces. Absorption of water accomplished by membrane pumps located in basolateral membrane of epithelium which creates an osmotic gradient. - egestion- limited absorption of minerals and vitamins; no digestion other than that produced by bacteria Histology same as basic pattern except:no villi or Paneth cells; increase numbers of goblet cells, intestinal glands present but secrete mainly mucusthe cecum and colon have a thin longitudinal muscle layer except for three evenly distributed ribbons of muscle known as Taenia coli; these cause the colon to pucker into pouches (haustra). Epiploic (omental) appendices are seen here and are fat filled pouches of the serosa layer.anal canal and rectum have no Taenia coli but well developed long. muscle to propel fecesepithelium is simple columnar (but changes to stratified squamous in rectum and anal canal)Vermiform appendix –extension of cecum contains a large amount of lymphoid tissue-the cecum and appendix are supplied with blood by the terminal branch of the SMAAscending Colon –retroperitoneal in most; supplied by SMA through the right colic arteries; drain into SMV, lymphatics ultimately drain into superior mesenteric lymph nodesTransverse Colon –most mobile of large intestine, held by transverse mesocolon and phrenicolic ligament-supplied mainly by middle colic artery from SMA; venous and lymphatic drainage same as ascendingDescending Colon –retroperitonealSigmoid Colon –S-shaped, connects descending with rectum; long epiploic appendices-sigmoid and descending supplied by branches of IMA through the left colic and sigmoid arteries (the left, middle, right and sigmoid arteries anastomoses forming the marginal artery of the colon-blood drained into IMV and lymph flows into inferior mesenteric lymph nodesRectum and Anal Canal –special features: transverse rectal folds and flexures, anal columns, valves, sinuses, external and internal sphincter musclesDefecation reflex:processed fecal matter accumulates in rectumleads to increase rectal pressure to a certain set point (dictated by habit)sensors inform CNS which leads to urge to defecate* and initiates defecation reflexinternal sphincter relaxesadmitting feces into anal canalincrease pressure on external sphincterunder voluntary control, external sphincter relaxeslong. rectal muscles contract to increase rectal pressure to evacuate feces*urge to defecate can be denied; smooth muscle of rectum relaxes & the int. sphincter contractsExcretory SystemPRIVATE Excretory systems remove waste products from the internal environment. Wastes such as CO2, heat, salt, urea, bilirubin, urochrome, and water are removed by various organs including the lungs, liver, large intestine, skin and, mostly, the kidneys.Excretory organs and associated waste productsOrganEssentialIncidentalLungsCO2H20, heatGI tract'solids", secretionsH20, heat, C02, saltsSkinheatH20, C02, saltsLiverbile pigments--------KidneysH20, urea, saltsCO2, heatUrinary System: kidney ureters urinary bladder urethraUreters:-27 cm long (humans), retroperitoneal: three layers:1. mucosa - transitional epithelium + rugae2. muscular - smooth muscle layer (LOCI)3. adventitia - fibrous coat continuous with parietal peritoneum-peristalsis moves urine jets down the ureters at a rate of 1-5 jets/min-normally constricted at three sites: junction of real pelvis, crossing pelvic inlet, and passage through bladder wall (bladder wall acts as one way valve)Urinary Bladder- muscular sac serves as reservoir for urine-retroperitoneal, sitting in a potential space (between parietal peritoneum and pelvic floor)-gross anatomy: apex, fundus, body, neck- three openings in floor of bladder: 2 lateral –for ureters and 1 medial –for urethra; triangular area formed is called the Trigone- four layers:1. mucosa -transitional epithelium + rugae2. submucosa3. muscular -smooth muscle (3 layers –an inner and outer longitudinal and a middle circular layer)-circular fibers in Trigone near the urethra thicken to form internal sphincter4. adventitia - fibrous coat continuous with peritoneum -below the internal sphincter surrounding the urethra as it passes through the body wall, there is an external sphincter made of skeletal muscleUrethra:- epithelium changes from transitional to stratified squamous- female - ~4 cm long- male - ~15-20 cm long; 3 portions1. Prostatic urethra -from bladder to pelvic floor; (2 cm), surrounded by prostate; lined with urinary epithelium; contains urethral crest, prostatic sinus, seminal colliculus, prostatic utricle2. Membranous urethra -portion that pierces body wall; surrounded by external sphincter;; epithelium changes to stratified columnar3. Penile urethra -(~15 cm); surrounded by corpus spongiosum erectile tissue; epithelium changes to stratified squamousMicturition (urination)-stretch receptors in the bladder send signals to the spinal cord which sends motor output which triggers relaxation of the internal sphincter and contraction of the bladder; this causes pressure (stretch) at the external sphincter which is perceived as urgency by the brain. (To prevent urination the brain must increase motor output to the external sphincter; if the bladder is not too full the smooth muscle can adapt to the stretch). Eventually, conscious control over inhibitory neurons in the spinal cord trigger decreased stimulus to the external sphincter which then relaxes and urine is expelled (normal urination is therefore a passive process consisting of the relaxation of the external sphincter which allows the contracting bladder to void).Kidneys: KNOW GROSS ANATOMY: hilum, capsule, cortex, medulla, pyramids, columns, calyx, papilla, pelvis and where parts of the nephron are found Blood flow: renal a. interlobar a. arcuate interlobular a. afferent a. glomerular capillaries efferent a. peritubular capillaries ** interlobular v. arcuate v. interlobar v. renal v.** Juxtamedullary nephrons also give off vasa recta capillaries from their efferent arteriole which connects to the renal veins-the glomerulus is fed by the afferent arteriole and drained by the efferent arteriole (only arterial portal system in body) which gives off a number of peritubular capillaries that rap around various tubules to aid in reabsorption and secretionNephron (functional unit) (over 1 million in each kidney) consists of glomerulus, associated renal tubules, and its blood supply- renal tubules: : Bowman's capsuleproximal convoluted tubule (PCT)loop of Henledistal convoluted tubule (DCT)collecting duct (CD)- two types of nephrons:1. cortical nephrons -7/8 of all nephrons in humans; no vasa recta (loop of Henle short)2. juxtamedullary (JM) nephrons -1/8 of all nephrons; long loops of Henle with vasa recta extending into medullaPhysiology of urine formation:main forces which form urine:1. pressure filtration -carried out by the glomerulus and Bowman's capsule as the result of blood pressure2. reabsorption -primarily in PCT by both active and passive transport of substance from tubule into peritubular capillaries3. secretion -primarily in DCT; active transport of substances from the blood (peritubular capillaries into the DCT)4. Reabsorption of water (osmosis regulation) -loops of Henle and CD; regulate the active transport of salt into the medulla allowing water to flow down its concentration gradient and be reabsorbedFormation of low volume, hypertonic urine: (accomplished by JM nephrons)Posterior Abdominal Wall and Cavity-excluding back muscles, the interior of the cavity consists of three major muscles:quadratus lumborumpsoas majoriliacus-psoas major and iliacus combie to form the iliopsoas groupMajor Blood vessels of posterior wallAbdominal AortaPhrenicAdrenalLumbarsRenalGonadalCeliacSMAIMACommon iliacExternal iliacInternal iliacMedia sacralIVCPhrenicAdrenalLumbarGonadal (occasionally arise from renal)RenalCommon iliacExternal iliacInternal iliac-the internal iliac supplies most of the pelvic viscera and deep pelvic musclesPelvisPelvic Cavity-contains the urinary bladder, distal ureters, pelvic genital organs, rectum, BV, lymphatics and nervesBoundaries and features:-pelvic inlet, pelvic outlet, pelvic axis, pelvic canal-pelvic diaphragm (floor) –made from levator ani and coccygeus muscles-greater pelvis (false) –space between iliac crests and pelvic brim-lesser pelvis (true) –space between inlet and outlet-Pubic arch and angle –male & female differencesPerineum –area of trunk between thighs to buttocks, and coccyx to pubis; in males includes: penis, scrotum and anus; in females includes: vulva and anus (some restrict term area between vagina and anus only)-anal triangle and urogenital triangle-perineal body –convergence site for several pelvic muscles, supports pelvic organsReproductive SystemPRIVATE FUNCTION: -the production of sex cells to insure the survival of the species and provide a means of conduction to facilitate the union of gametes-to promote the generation, maintenance, and rearing of progenyGonads:-the reduction of chromosome number is accomplished by MeiosisMeiosis -has two parts (meiosis I and II) (review for exam)-meiosis I sorts chromatids by homologous pairs and then divides the cell placing one half the number of chromosomes in each cell-meiosis II lines the chromosomes in the equatorial plane but divides each at the centromere (similar to mitosis); each cell finally ends up with half the number of chromosomes and with one copy of each-Supplied by genital A&V, drainage of lymph to the lumbar or aortic lymph nodes not inguinalMale Testes: -encapsulated and lobulated by dense CT (tunica albuginea)-composed (chiefly) of seminiferous tubules (site of sperm production)-spermatogonia -> 1o spermatocyte -> 2o spermatocyte -> spermatids > spermatozoa-sperm anatomy: head, midpiece, tail, pronucleus, acrosome-two other major cell types found in tubules: Sertoli and Leydig cells-Sertoli cells function in: production of luminal fluid (ABP), secrete inhibin, phagocytize defective sperm and debris, stimulate sperm production, maintain testis blood barrier, and provide nourishment to developing sperm-Leydig cells -secrete testosteroneDuct System:-Rete testis -ciliated to move sperm to next duct-Vasa efferentia (ductus efferens)-Epididymis -highly convoluted tube lined with pseudostratified columnar with stereocilia (site of sperm maturation and storage)-Ductus deferens (seminal duct) -stores and transports sperm by peristalsis; enlarges distally into ampulla before forming ejaculatory duct-Ejaculatory duct -mixes sperm with secretion of seminal vesicle and transports seminal fluid to prostatic urethra during ejaculationAccessory Sex Glands:-Seminal vesicle -secretes alkaline viscous fluid rich in fructose (~60% of seminal fluid)-Prostate -secretes alkaline fluid to neutralize urethra and enzymes which control sperm clotting/declotting, etc. (~30% of semen volume); has both glandular and muscular component-Bulbourethral (Cowper's) gland -secretes mucus (lubricator) and a urine neutralizer into penile urethra (accounts for <5% of semen)Supporting Structures -Scrotum -external pouch to hold testes at a lower temperature to allow spermatogenesis; fatty fascia replaced by smooth muscle (Dartos tunic) that crinkles skin, and surrounded by a cremaster muscle-Spermatic cord contains vas deferens, testicular artery, cremaster muscle, lymphatics, autonomic nerves and the pampiniform venous plexus -helps to maintain lower temperature of scrotum-Penis -for deposition of sperm within female genital tract-consists of: a body (shaft) made mostly of erectile tissue (corpora spongiosum and cavernosum), fascia, BV ad skin; a glans penis which is covered by a loose skin the prepuce (foreskin) with its frenulum, corona, neck, penile raphe-root of the penis: crura of the caverosa and the bulb of the spongiosum-three muscles anchor the root of the penis: bulbiospongiosus, ischiocavernosus, and the transverse perineal muscles-erection and ejaculation are mainly a spinal reflex which are readily influenced by the brain; during erection the blood flow to the erectile tissue increases as well as a decrease in blood return from the same tissue. When stimulation is sufficient, a rhythmic contraction of the ducts, urethra and muscles at the base of the penis expels the seminal fluid.Erection is mainly a parasympathetic reflex on the blood vessels controlling blood flow into the erectile tissues of the penis. Ejaculation is due to increasing sympathetic activity on the muscles of the ducts involved (urethra, vas deferens, ejaculatory ducts) triggering peristalsis. And a spinal somatic motor reflex controlling the pelvic muscles involved during ejaculation.Hormonal Control: GnRH FSH & LH (neg. feedback) Sertoli Leydig Testosterone Inhibin TBP FemaleOvariesLayers: outer germinal layer -misnamed (scientific faux pas), tunica albuginea (CT), and stroma -divides ovary into cortex (with follicles) and medulla (with blood supply)-ovarian follicles: -1o follicles ( with 1o oocyte) -> 2o follicles -> Graafian follicles (with 2o oocyte) -follicle anatomy: theca cells, follicular (granulosa) cells, oocyte -ova cell division as follows:oogonia -> 1o oocyte -> 2o oocyte -> ovumoogonia undergo mitosis only in the embryo (therefore a woman is born with all of the eggs she will ever produce); meiosis begins in the fetus and then stops during meiosis I; it will resume at puberty when pituitary hormones regulate the menstrual cycle; meiosis II will begin and stop as well, and will not complete unless fertilization occurs -egg anatomy (ovulated) -oocyte, zona pelucidum(ZP), corona radiatacorona radiata = follicular cells; ZP = noncellular membrane used to bind sperm of same speciesDuct System: Fallopian tubes (oviducts) -transport the ovum(must catch ovulated egg), site of fertilization and plays a role in the capacitation of sperm, etc. -three layers:mucosa -ciliated columnar cells which move and feed the ovummuscularis -peristaltic contractions to move ovum and spermserosa -continuous with visceral peritoneum -terms: infundibulum, fimbria, ampulla, and isthmus -supported by mesosalpinx Uterus -houses and supports fetus -anteverted and anteflexed; - body, cervix, fundus, isthmus, cervical canal, internal and external os -layers: perimetrium (visceral peritoneum), myometrium (smooth muscle), endometrium -two layers:1. stratum functionalis -nourishes fetus and is shed2. stratum basalis -produces functionalis-supported by broad lig., suspensory lig. of ovary, and round lig.Vagina -allows for passage of fetus and menstrual flow and is receptacle for male intromittent organ and sperm, highly distensibleHormonal Control of the Menstrual Cycle -divided into follicular (proliferative) and luteal (secretory) phase averages about 28 days Follicular Phase: (proliferative)-starts with menstrual flow (menses) which continues for about five daysthe flow is the breakdown of the stratum functionalis from the previous cycle-during this time FSH and LH are in nearly equal concentrations and some follicles are allowed to develop and complete meiosis I; additionally, the ovary is producing large quantities of estrogens with some progesterone-by about day 14, both FSH and LH surge upward in concentration (especially LH), this triggers ovulation; at approximately the same time, estrogen levels fall and progesterone levels rise.-the follicular phase is also known as the proliferative phase for its effect on the endometrium which greatly increases in size during this period Luteal Phase:(secretory)-this increase in progesterone is accomplished by the conversion of the ruptured follicle into the corpus luteum; if pregnancy does not occur, the corpus luteum regresses at about day 28 and forms the corpus albicans (scar)-the growth of the stratum functionalis is maintained during the luteal phase by the action of progesterone. The fall in the levels of this hormone contributes to the shedding of this layer during the next menses.-this time is secretory because the uterine glands begin to secreteSupporting Structures:Vulva (external genitalia)mons pubis -elevation of adipose tissue just anterior to urethra -has two longitudinal folds of skin labia majora -homologous with scrotum; space between is pudendal cleft; unite at the anterior and posterior commissurelabia minora –contains vestibule, clitoris, frenulum of minora at posteriorclitoris -homologous with penis (high density of sensory neurons); body, glans clitoris, prepuce and frenulum; has erectile tissue homologous with cavernosavestibule -cleft between minora containing the urethral and vaginal orifices, hymen and openings of a number of mucoid glands (paraurethral, greater and lesser vestibular glands)--also contains paired bulbs (erectile tissue)Accessory Sex Glands -paraurethral -secretes mucus (homologous with prostate) -greater vestibular (Bartholin's) gland -mucoid secretion (homologous with Cowper's gland) -lesser vestibular glands -microscopic gland which aid in lubricationDevelopment:-embryo gonads are sexually indistinguishable; under influence of testosterone the gonads will develop into testes; otherwise ovaries will develop. The same is true for most of the subsequent generation of the appropriate duct system.Lymph drainage of both ovaries and testes is to lumbar and aortic nodes not inguinalAging: -menopause, little pathological change with agePathologies and Clinically Related TopicsSTDs and contraception Developmental AnatomyTotal time from conception to birth is 38 weeks, the first 8 weeks constitute the embryonic period, the remainder is the fetal period.Week 1:Fertilization (conception) -the union of gametes (sperm and ovum) with the corresponding restoration of the full complement of chromosomes (produced by the fusion of the pronuclei); this forms the zygote.Cleavage -increase in the number of cells making up the zygote through cell division; however, with each cell division, the cells become progressively smaller in size (in order to re-establish the proper surface area to volume ratio). This period ends with the formation of the morula (a solid sphere of cells of the proper size). (Note: cell division still continues but the cells now retain their initial size). Cleavage takes place as the zygote drifts down the oviduct and lasts for 3 days. By day 4, the completed morula (about 60+ cells) arrives at the uterus. Blastocyst Formation - the morula rearranges itself into a hollow sphere (blastocyst with its blastocyst cavity) producing a bilaminar embryo consisting of an inner cell mass (which will form the body of the embryo and some extra-embryonic structures) and a outer trophoblast layer (which will become the chorion).Implantation and placenta development -By day 6, the blastocyst begins to burrow into the endometrium (inner most layer of uterus) to establish contact with maternal blood vessels. The trophoblast secretes enzymes which dissolve maternal tissue allowing the embryo to sink into the endometrium until it is bathed in maternal blood. As the embryo sinks the endometrium heals above it sealing the embryo completely within maternal tissues. The trophoblast thickens and begins to form extensions called chorionic villi to increase surface area. As time goes on, other extra-embryonic membranes (allantois, amnion and yolk sac) will form; as well as, a fetal blood supply to the chorion. This will eventually form the umbilical cord.Week 2:Inner cell mass divides into a two layered embryo (epiblast and hypoblast) , additionally the amnion and yolk sac formWeek 3:Gastrulation and Formation of Primitive Streakforms a three layered embryo as mesenchymal cells move between epiblast and hypoblast; these 3 layers form the 3 primary germ layers:ectoderm –destined to form epidermis of skin and the nervous systemmesoderm –will form all connective tissues, kidneys, gonads, muscle, etc.endoderm –forms the lining of the gut, lungs, liver, and germ cellsnotochord and neural tube formation begins; formation of organizing centersmesoderm further divides into somites, intermediate mesoderm and the lateral plates Week 4: Neurulation CompletesMovement of the ectoderm above the growing notochord to form a hollow tube which will become the CNS.Growth of lateral walls joins at ventral side completing the tube like body of the embryoThe heart begins to beat.Weeks 5-8: Growth and Limb bud formationsomatic mesoderm and part of some of the somites reorganizes to form paddle-like extensions that will eventually form the limbsFetal Period (9 weeks until birth): Morphogenesisgeneration of organ systems with corresponding specialization of cells and growth in size, this periods ends with birthBirth -delivery of child and placenta; hormonal control of birth process (PGs, oxytocin);three stages-Stage I (Effacement and Dilation) with 3 phases-latent, active and transition-Stage II (Expulsion) -delivery of fetus-Stage III (Afterbirth) -delivery of placentaBreast Feeding –prolactin activates mammary tissue, oxytocin causes let downInfancy -period of rapid growth which last until childhood (2 yrs.)Childhood - period of steady growth that last until puberty (9-11 yrs.)Adolescence (puberty) - period of 2 massive growth spurts and onset of sexual function; ends at adulthood (19-22 yrs)Adulthood and Aging-gradual decline of bodily systems, decreased homeostatic response and diminished response to stress, declines usually begin around age 30-40 with different organs and individuals aging at different ratesGrowth process influenced by genetics, endocrine function and environmental factors (nutrition and disease)-typically characterized by cell division and protein synthesis Bone growth: review anatomy of long bone: epiphysis, diaphysis, medullary cavity, epiphyseal plate, cartilage -cartilage of epiphyseal plate allows bone to lengthen and is eventually completely replaced by bone -2 major growth periods: Pre-pubertal (first 2 years) and puberty (sex differences) -to obtain genetic max, a person needs: adequate nutrition (protein, vit, FA, minerals, sufficient energy) and be relatively disease free (if sick for extended time most children can perform catch-up growth)-prenatal growth is largely independent of GH, T3 and sex hormones; however, these are very important for postnatal growthUpper Limb: ArmBony Structure:Pectoral girdle: scapulae and clavicle (review from thorax)Brachium (arm): Humerus with elbow jointAntebrachium (forearm): Radius and UlnaWrist: carpals (Scaphoid, lunate, triquetrum, pisiform, trapezium, trapezoid, capitate, hamate)Hand (manus): metacarpals and phalangesHumerus: head, two necks, deltoid tuberosity, capitulum, trochlea, tubercles, intertubercular groove, olecranon (cubital) fossa, epicondylesUlna: head, neck, trochlear notch, styloid process, coronoid process, olecranon process, radial notchRadius: ulnar notch, head, neck, tuberosity, styloid process, dorsal tubercleFascia: Pectoralis fascia –sheaths the pectoralis major and is continuous with abdominal fascia and the axillary fasciaClavipectoral fascia –extends from axillary fascia, encloses the pectoralis minor and attaches to the clavicle (has 2 parts: superior to pectoralis minor is the costocoracoid membrane and inferior to pectoralis minor is the suspensory ligament of the axillaBrachial fascia –continuous with axillary and antebrachial fascia; attaches to the humeral condyles and olecrannon process of the ulnaAntebrachial fascia –splits to divide the muscles into flexor and extensor compartments, the interosseous membrane connects radius and ulna. Thickens posteriorly to form the extensor retinaculum (keeps extensor tendons in position) and anteriorly forms the flexor retinaculum attaches to trapezium and hamate to form the carpal tunnel through which the flexor tendons and median nerve passMuscles:Pectoral Girdle: Deltoid, Supraspinatus, Infraspinatus, Subscapularis, Teres Major and MinorBrachium: Biceps brachii, Triceps Brachii, BrachialisAntebrachium: Flexors, Extensors, pronators and supinatorsMajor Nerves: Musculocutaneous, radial, median, ulnar nervesVessels: Subclavian, Axillary, Brachial, Radial and Ulnar A&V, plus Basalic and Cephalic veins-more detail to be seen in cadaversLower Limb: LegBony Structure:Pelvic girdle: Sacrum and Os Coxae (review from thorax)Femoral (Thigh): Femur with knee joint and patellaCrural (lower leg): Tibia and FibulaAnkle: Tarsals (clacaneus, talus, cuboid, navicular, cuneiforms (medial, lateral, intermideiate)Foot (Pes): metatarsals and phalangesFemur: head, neck, greater and lesser trochanter, intertrochanteric crest and line, gluteal tuberosity, linea aspera, condyles, epicondyles, intercondylar fossa, adductor tubercle, patellar surfaceKnee: Collateral ligaments, Anterior and Posterior Cruciate ligaments, Patellar ligament, Quadriceps ligament, Patella, MenisciTibia: condyles, intercondylar eminence, tibial tuberosity, medial malleolus, fibular notch, anterior crestFibula: head, neck, tuberosity, lateral malleolusFascia: Fascia lata –deep fascia of the thigh, sheaths the thigh major and is continuous with abdominal fascia, thickens laterally to form the Iliotibial tract (the aponeurosis of the gluteus maximus and tensor fascia lata, this tract inserts at Gerdy’s tubercle)-divides the muscles of the thigh into three compartmentsCrural fascia –continuous fascia lata and tibia periiosteum proximally, distally is thin except where it forms the extensor retinaculum, divides lower leg into three campartmentsMuscles:Pelvic Girdle: Gluteals, Iliopsoas, Tensor fascia lata, Femoral Region: Pectineus,Sartorius, Gracilis, Quadriceps femoris, Biceps femoris, Adductor longus, Adductor brevis, Adductor Magnus, Semitendinosus, Semimembranosus Antebrachium: Plantar Flexors, ExtensorsMajor Nerves: Femoral and Sciatic nerves and their branchesVessels: Femoral, Anterior and posterior tibial A&V, Greater and Smaller Saphenous veinsNote: Femoral Triangle and Femoral Sheath-more detail to be seen in cadaversAppendixThe CellCell MetabolismTissuesThe Cell PRIVATE The cell is the basic structural and functional unit of the body; ranging in size from 2-120 ponents:1. Cell membrane - made of a fluid phospholipid bilayer, proteins, cholesterol and associated carbohydrates- Contains proteins that serve as receptors and channel gates- Two types: a) Integral proteins - embedded in plasma membrane b) Peripheral proteins - associated with membrane surface- Selectively permeable - allows certain particles to pass more easily than othersMovement of particles:Diffusion - the movement of particles from an area of higher concentration to an area of lesser concentration; until equilibrium is reachedDiffusion through a Membrane:-the cell membrane will not allow ionic or highly polar compounds to follow their concentration gradient (highlow) -only water*, oxygen, carbon dioxide, and non-polar substances (steroids, fats, etc.) are allowed to pass freelyMediated Transport-facilitated diffusion - uses a protein to carry a molecule across the membrane along its concentration gradient (high low); thus no additional energy is usually required-channel proteins in the membrane create tunnels to let specific ions cross the membrane; all other substances must be transported across the membrane by specific transporters-active transport - uses a carrier protein to carry a molecule across the membrane against its concentration gradient (L H); thus this process requires the expenditure of energy (ATP -> ADP + P) (primary and secondary (or co-transport))OsmosisOsmosis - is the net diffusion of water down its concentration gradient when the movement of solute is preventedosmolarity - the total solute concentration (number of particles) in a solution (the higher the osmolarity of a solution the lower the water concentration)isotonic solutions - has the same concentration of non-penetrating solutes as normal extracellular (and also intracellular) fluidhypotonic solutions - have less solute than normal intracellular fluid (therefore, more water) and cause a cell to swellhypertonic solutions - have more solute than normal intracellular fluid (ergo, less water) and cause the cell to shrinkEndo and Exocytosis-cell membrane folds forming a vesicle with some extracellular contents is endocytosis (phagocytosis)-when a vesicle fuses with the cell membrane and dumps its content into the extracellular space-the result of both of these processes is not only transport but cell membrane cycling as wellMembrane Potentials-the electrical charge distribution across the membrane is unequal; this results in a voltage across the membrane termed a potential-this created by permeability properties of the membrane, the action of the Na-K pump, and the presence of non-diffusible negatively charged compounds within the cell membraneMembrane Junctions:1. desmosomes - cell membranes (20 nm separation) which are anchored to each other by extracellular protein and fibers projecting from the cytoplasmic surface of each cell; chiefly for mechanical support; two types: spot and belt2. tight - cell membranes with virtually no extracellular space between them; membranes in close contact (2-4) nm apart) which allows particles from passing around the cells3. gap - cell membranes in close contact (2-4 nm apart) which allows channel proteins in opposing membranes to line up allowing ions to pass from cytoplasm to cytoplasm2. Cytoplasm - the fluid found inside the cell external to the nucleus and its constituent molecules; consists of organelles and the cytosol3. Organelles - permanent structures which serve a special purpose a. Nucleus - houses the genes (DNA - in the form of chromatin (DNA + proteins) which contains the genetic blueprint of all proteins needed for life (and RNA's)- has a double membrane (nuclear envelope) with pores- contains nucleoli composed of ribosomal RNA (rRNA) which, with proteins, form ribosomes in the cytoplasm-messenger RNA (mRNA) is formed when the DNA is read (transcription); the mRNA represents the sequence of codons (instructions) for the formation of a specific proteinProtein Synthesis -Transcription and Translation -Central Dogma of BiologyTranscription -DNA is 'read' into RNAgene- is that part of a DNA molecule which codes for an functional RNA molecule-DNA strand is split and an RNA copy of the DNA code is made; control of this process is accomplished by binding of enzymes to specific areas of the DNA molecule (promoter regions, enhancer regions)mRNA -codes for a specific proteincodon -series of three base sequences which code for a single amino acid in mRNA-not all areas of the mRNA code for protein initially; there are exons (that portion of the mRNA which actually codes for amino acids) and introns ('spacer' sequences between exons which do not code for amino acids)post-transcriptional events -modification of original mRNA transcript; for example: cutting out introns, stabilizing, etc. b.Ribosomes - read the mRNA and produce the protein (translation) (note: protein is made of amino acids; DNA and RNA is made of nucleic acids - the DNA and RNA code for the sequence of amino acids in a protein which gives the protein its uniqueness); the amino acids are transported to the ribosomes by transfer RNA (tRNA) molecules. Translation -converting mRNA into protein initiation -binding of mRNA and first tRNA, assembling a functional ribosome elongation -arrival of other tRNA molecules in the open ribosome "reading window", which bind their anti-codon regions to mRNA codons; the amino acids are then bound together by an enzyme on top of the ribosome. The ribosome then shifts to a new codon and the process is repeated termination -translation stops when a termination (stop) codon is reached; the ribosome disassembles releasing the proteinpost-translational events -further chemical manipulation of the protein, folding, or insertion into endoplasmic reticulum for packaging into vesicles- if the protein being made functions within the cell the ribosome remains free in the cytoplasm and the protein is released directly into the cytoplasm- if the protein is to be excreted or put into a cell membrane then the ribosome/mRNA complex attaches to the endoplasmic reticulum and the protein is released into the lumen of the ER c.Endoplasmic reticulum (ER) - system of membrane channels which functions to transport products (special proteins and lipids) from the nucleus or ribosomes to the Golgi complex; can be either smooth (ribosome free) or rough (with ribosomes) in appearance d.Golgi complex - made of a stack of bag-like membrane pouches which serve to package products into vesicles (membrane sacs) for later fusion with the cell membranes e.Mitochondria - double membrane, rod shaped organelle whose main function is the production of energy for the cell in the form of ATP through the metabolism of sugar (inner membrane folded to form cristae) f.Cytoskeleton - gives support and movement the cell and its internal components- microfilaments - (7 nm in dia.) made of actin contractile properties; used in the movement of internal structures and the cell membrane - intermediate filaments - (15 nm in dia.) myosin contractile filaments found in muscle cells; but found in all cells in a non-filamentous form- microtubules - (25 nm in dia.) made of tubulin proteins; arranged into thin, hollow tubes used mainly for structural support g.Centrioles - a ring of nine triplets of microtubules; function in the movement of chromosomes during cell division (when inactive found near nucleus as the centrosome); may also play a role in the construction and functioning of flagella and cilia h.Flagella and Cilia - consist of nine pairs of microtubules forming a ring around two central microtubules- flagella are long and few in number; cilia are short and many in number; both can be used in the movement of the cell or in the movement of extracellular substances over the cell surface i.Vesicles - any membrane bound sac found in the cytoplasm which usually carries some substance; for example:1. lysosomes - carry digestive enzymes to degrade foreign particles or old organelles2. peroxisomes - carry enzymes capable of neutralizing free radicals of oxygen (i.e. hydrogen peroxide - a byproduct of normal metabolism)3. vacuoles - usually found only in plants: used to store large quantities of substances and may take up 50-90% of the cell interior j.Microvilli - finger-like extensions of the cell membrane used to increase cell surface area in absorption and secretionk.Cytoplasmic Inclusions –storable forms of food and pigments (glycogen granules, fat droplets, melanin granules, etc.)Cell Division (mitosis -the exact duplication of a cell; used in asexual reproduction and growth) or (meiosis -the reduction of the number of chromosomes by half and form gametes; used in sexual reproduction)The Cell Cycle M -mitosis (division of cell) G1 -gap one; synthesis of proteins necessary for gene replication S -synthesis of DNA G2 -gap two; synthesis of proteins necessary for mitosisCell divisionMitosis -cell division where each daughter cell has the same number of chromosome as the parent cellEx: humans cell have 46 chromosomes; this number is conserved in every replicationdefinitions to know:chromosomes -composed of a highly coiled DNA molecule which contains genetic informationDNA -composed of double strand of repeating nucleotides arranged in a double helix; each strand consists of:1. nitrogen bases (adenine, thymine, guanine and cytosine)2. sugar backbone (deoxyribose)3. a phosphate groupchromatid -is a chromosome which has replicated itself and is still attached to its duplicate by a structure called the centromereKNOW THE STAGES OF MITOSIS and some major events that occur in each stage.Aging progressive failure of the body's homeostatic adaptive responses-loss of function and capacity to respond to stressCellular changes include:a. decrease proteinb. decrease waterc. increase cross-linking and other chemical damaged. increase in age pigments (lipofuscin) Some Theories:1. Collagen cross-linking -extracellular proteins increasingly bind to one another with age, therefore the cells are increasingly isolated and cutoff from valuable nutrients, etc.2. Programmed Theories gene control - genetic trait which turns on and begins to slow down and turn off vital life processesBiological clocks –pineal, brain, immune system3. Free-radical theory -highly reactive oxygen molecules generated by normal metabolism increase in appearance and cause damage to vital enzymes and even DNA4. Somatic Mutation theories -environmental damage to DNA or protein synthesis machinery of cellMetabolismPRIVATE Metabolism - all of the chemical reactions which occur in the cell (each reaction requires a specific enzyme)Metabolic reaction - R P R = reactants; P = products -the P may have more or less energy than the R: if the reaction yields energy then it is exergonic; if it uses energy then it is endergonic -the reactions are reversible; therefore the terms P and R are relative, since the products may react to form the reactants -all reversible reactions approach a dynamic equilibrium (unless kept from doing so); the equilibrium (balance point) reached may or may not be an equal one. That is, each reaction has its own ratio of products and reactants.Metabolic Pathway -is a series of reactions; most are linked with other pathways using the products of one path as the reactants for another. Two Kinds of pathways:1. Degradative (Catabolism) -stepwise breakdown of large compounds into smaller ones2. Biosynthetic (Anabolism) -stepwise assembly of small compounds into large compoundsEnzymesenzymes(E) -proteins which selectively catalyze (speeds up) a reaction without entering the reactionsubstrates(S) -any substance that an enzyme acts upon (same as reactant)cofactor -any non-protein substance which aids an enzymebinding sites -any area of a protein to which a substance binds by non-covalent forcesmodulator -any substance which changes the functioning of a proteinGeneral reaction: S + E ES E + PCharacteristics of enzymes: -binding sites -for substrates (called the active site) and some for modulators these substances are always bound by forces that are non-covalent -catalyzes reaction; (speeds up the rate of the reaction; the enzyme is not changed in the reaction). It does this by binding the substrates (non-covalently). The close proximity of the substrates and the stress caused by the enzyme binding increases the chance (by lowering the energy needed to start the reaction) for the substrates to react to one another. -specificity -an enzyme only catalyzes one reaction -affinity -is the strength to which a substrate binds to the active site -affected by pH and temperature (all proteins are active only within a certain range of pH and temperatureControl of Enzyme Function:-by the concentration of the substrate and enzyme (saturation)-inhibition -substances which bind to the active site but are not a substrate for the enzyme; this prevents the substrate from binding (this is a form of competition)-allosteric modulation -control over enzyme by turning it "ON and OFF"; an additional binding site reacts with a modulator which changes the 3-D shape of the enzyme; thus affecting the active sites-covalent modulation -still turns enzyme 'On and OFF', but 3-D shape can only be changed by covalently binding another molecule to the enzyme (these enzymes only have active sites) usually phosphate groups are bondedCofactors -any non-protein substance which assists an enzyme -coenzyme -large organic cofactors which accept or contribute atoms in an enzymatic reaction (commonly H atoms are transferred) Ex. NAD, FADCellular Respiration -burning (oxidation) of glucose to yield energy (in the form of ATP) -ATP will be made by substrate phosphorylation or by oxidative phosphorylationAerobic -energy production in the presence of oxygen; Overall reaction: glucose + oxygen water + CO2 + energy(ATP)Glycolysis -occurs in the cytoplasm; Overall reaction: glu + 2NAD + 2 ADP 2 pyruvate + 2 NADH + 2 ATP -actually consists of several reactions which initially use 2 ATP but eventually produces 4; so that 2 are netted-note: one glucose forms two pyruvate; therefore, all of the following are written assuming that both pyruvates and their products remain in the cycle (that is, one glucose)Transition reaction -pyruvate is transported into mitochondria and converted to acetyl-CoA 2 pyruvate + 2 NAD + 2 CoASH 2 acetyl-CoA + 2 CO2 + 2 NADHKreb Cycle -series of reactions which regenerate located in matrix of mitochondria2 acetyl-CoA + 6 NAD + 2 FAD + 6 HOH 4 CO2 + 6 NADH + 2 FADH + 2 ATPElectron Transport Chain (oxidative phosphorylation) uses energy transfer to build an electrochemical gradient which powers ATP production (chemiosmosis) -oxygen is the final acceptor of the electrons and forms water as a waste product -1 NADH => 3 ATP; 1 FADH => 2 ATP in the respiratory chain therefore counting up what was formed in the above reactions:10 NADH = 30 ATP2 FADH = 4 ATP4 ATP from direct phosphorylation in the above reactions 38 ATP total for every glucose molecule entering the cycleNOTE: NADH is not transportable across the mitochondria membrane directly, but can indirectly be transported by several different shuttle pathways; the one used here yields the same number of NADHs that utilizes it. Others require energy from the NADH molecule and thus some of the energy is lost. Hence why many books write that one molecule of glucose yields 34 ATP Anaerobic -glycolysis can still function, however the NADH produced can react with pyruvate to form lactate (or some organisms may convert pyruvate to alcohol); in humans, lactic acid is transported in the blood to be converted into pyruvate by the liver, the NAD+ produced can then reenter glycolysis to breakdown more glucose and produce more ATPCarbohydrate Metabolism -sugars other than glucose can be chemically altered into glucose or one of its derivatives found in glycolysisProtein Catabolism -proteases breakdown proteins into amino acids-amino acids may have their amino group (NH) removed (forming a keto acid) and structure rearranged to form one of the compounds in the Kreb or glycolytic cycles, thus yielding energy or other useful materials-loss of an NH group is accomplished by either deamination or transamination-deamination (the removal of NH from an amino acid) forms a keto acid plus a molecule of ammonia (NH3), ammonia is converted in the liver to urea for excretion by the kidney -transamination simply transfers the NH group from the amino acid to a keto acid which forms a new amino acidFat Catabolism -fats breakdown to fatty acids and glycerol-glycerol ( a 3 carbon sugar) can easily enter glycolysis-fatty acids are chopped up into two carbon segments which are attached to CoA; these then enter the Kreb cycle -known as Beta Oxidation. The process of clipping off 2-carbon segments produces NADH and FADH; therefore, one molecule of fatty acid produces an enormous amount of ATPC-C-C-C-C-C-C-COOH + CoASH + ATP C-C-C-C-C-C-C-CO-CoA + HOH8-C fatty acid8-C fatty acid linked to CoAC-C-C-C-C-C-C-CO-CoA + NAD+ + FAD + CoASH NADH + FADH2 + C-C-CoA + |C-C-C-C-C-C-CoA |______________________________________________| The last acetyl-CoA does not produce any co-enzymes; therefore the gross yield is 63 ATP with a net gain of 62 ATP. TissuesOrganization of the Body:Cells -basic unit of lifeTissues -aggregates of cells with similar characteristicsOrgans -combinations of tissues to perform a specific functionOrgan Systems -combinations of organs to perform some overall functionTissues:Tissues -are a group of similar cells and their associated extracellular substances which carry out a specific taskFour basic types:1. Epithelium -covers body surfaces whether internal or external; also functions to adjust degree of friction on the surface, absorption, defense, excretion, etc.-arranged in layers: simple (single), stratified (multiple) or pseudostratified (single but appears as multiple)-cell shapes: squamous (flat), cuboid (cube), columnar, and transitional (able to change shape and stratification) KNOW WHERE EXAMPLES OF EACH CAN BE FOUND -Internal environment consists of extracellular fluids and substances and cells; about 80% interstitial and 20% plasma (intracellular fluid is much different in composition than extracellular)2. Muscle -has the ability to contract; therefore functions in the movement of the body, its parts, and the contents within the body; three types:a. Skeletal -muscle which moves the skeleton; voluntary and striatedb. Cardiac -muscle in the heart, involuntary and striatedc. Smooth -associated with tubes and ducts, involuntary and non-striated3. Nervous tissue -conducts and initiates electrical signals (action potentials); controls and coordinates all body functions, forms the mind and emotion, and allows the body to respond quickly to stimuli (cells are called neurons)4. Connective Tissue (CT) -protects, supports and binds together other tissues and organs; consists of cells and extracellular matrix which contains ground substances (water, organic cements, etc.) and fiber (collagen, elastin, and glycoproteins); classification:I. Post-natal CT 1. CT proper -cells are fibroblasts (except for fat - adipocytes)Loose CT -found when tissue must be held in place but needs much space for fluid and vessels; collagen dominates; -includes areolar, elastic, reticular, and adiposeAreolar -found in subcutaneous layer of skin, blood vessels, nerves, etc.Elastic CT -found when great flexibility need, elastin fibers dominate; found in large arteries, dermis, lungs, bladderReticular CT -forms a supporting network; collagen, elastin and glycoproteins are present; found in stroma of organs and bone marrowAdipose CT -storage and metabolism of fatb. Dense CT -found when great strength and rigidity needed; collagen is densely packed in either a regular or irregular arrangement; found in tendons, ligaments, organ capsules, fascia, sclera of eye 2. Cartilage -nonvascular supporting tissue; cells are called chondrocytes; semi-fluid extracellular matrix; 3 types(based on fibers present):a. fibrocartilage -collagen (rigidness); found in pubic symphysis, intervertebral discsb. elastic cartilage -elastin (flexible); found in epiglottis, pinnac. hyaline cartilage -more ground substance than fibers (mostly water), most abundant cartilage of the body; found in nasal septum, intercostal cartilages, larynx, trachea, and articular surfaces 3. Bone -vascular supporting tissue, cells called osteocytes, provides support to body, stores minerals and the marrow produces blood cells 4. Blood -supports metabolically, no fibers present, high water content; consists of red blood cells (carry oxygen) and white blood cells (defense)II. Embryonic CT –found mainly in embryo a. mesenchyme -cell from which all other CT arise, some cells persist in adult as stem cells b. mucous CT -found in umbilical cord of fetus ................
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