Chapter 9 Notes - Muscles & Muscle Tissu



Notes – The Muscular SystemStructure of a Skeletal Muscle - A muscle is an organ containing muscle fibers, CT, BV, nerve fibersDefine fascia:_____________________________________________Compare a tendon with an aponeuroses:Match each connective tissue layer with what it encloses:Individual muscle fiber enclosed by: _________________________________Bundle of muscle fibers (fascicle) enclosed by: ________________________Entire muscle enclosed by: __________________________________TWO important functions of the connective tissue wrappings___________________ & __________________ all parts of a skeletal muscle.provide exit and entry points for ________________&__________________Define compartment: ____________________________________________________ and read about compartment syndrome.Define fasciotomy _______________________________________________________ and look up a short video about it on the Internet.Thought Question: Skeletal muscle is dependent on its:Nerve supply because it cannot _____________ without nerve stimulationBlood supply because it uses tremendous amounts of ________________ which requires delivery of oxygen & glucose and it gives off lots of ______________________ that must be removedright3376589Skeletal muscle fibers (cells) - Skeletal muscle cells are multinucleate with the nuclei located just beneath the plasma membrane________________________: specialized plasma membrane of a muscle fiber ___________________________: cytoplasm of a muscle fiber______________________________: unique oxygen binding protein in a muscle_______________________________ – long parallel structuresBanding patterns/striations reveal the working structure: For each of the following structures, be able to DESCRIBE STRUCTURE & FUNCTIONS, RECOGNIZE ON A DIAGRAM OR MICROGRAPH!ActinMyosinTroponinTropomyosinSarcomereI bandZ lineA bandH zoneM lineSarcoplasmic reticulumTriadTransverse tubulesTerminal cisternaeSkeletal Muscle Contractions - Mechanism of contraction (on a cellular level) - Regulation of Contraction – how muscle knows WHEN to contractNeuromuscular junction - Each axon terminal forms junction with single muscle fiberSynaptic cleft – fluid filled gap between nerve and muscleNerve and muscle do not make contactImportance: prevent continuous stimulation (acts as an ON/OFF switch)Stimulus for contractionVesicles in axon terminal filled with neurotransmitter – chemical released by neuron upon arrival of action potential (aka. Nerve impulse)The neurotransmitter for skeletal muscle is acetylcholine (ACh)Neurotransmitter crosses synaptic cleft and attaches to receptors on the sarcolemmaSarcolemma becomes temporarily permeable to sodium (Na+)Na+ ions rush into muscle cell which reverses electrical conditionsAction potential is generated and propagated along sarcolemma and down T tubules deep into muscle fiberOnce initiated – action potential is unstoppable (all or none principle) resulting in full contraction of that particular muscle fiber (cell) Excitation-contraction coupling (connection between stimulation of fiber and contraction of fiber)Action potential "wave" travels along sarcolemma and deep into T tubules.This triggers Ca2+ release from terminal cisternae of SRRole of ionic calcium in regulating muscle contraction — in the absence of ionic calcium, the _________________________ (a regulatory protein) blocks the binding sites on the actin so the filaments cannot attach to each other. When ionic calcium becomes present, it is avidly bound by the ______________________ (another regulatory protein) which causes the tropomyosin to change shape thus exposing the binding site allowing attachment of the actin and myosin. Contraction occurs : Sliding filament theory – HOW a muscle contracts - What causes the filaments to slide?cross bridge attachment - Myosin head has __________ energy configuration and binds to actin binding site in the presence of Ca2+power stroke — ATP provides energy to bend and pull actin filament toward center of sarcomere – results in shortening of ~1% of the sarcomerecross bridge detachment — ATP also provides energy causing cross bridge to detach: FYI: rigor mortis – _____________________________ ___________________________________________________________"cocking" of the myosin heads — energy returns myosin head to upright high energy configurationSafeguards - When nerve stimulation stops:Ach is destroyed by acetylcholinesterase (AChE) to prevent continued contractionSubstances such as certain organophosphates found in pesticides and fertilizers destroy AChE causing convulsionsRelaxation - Action potential ends Ca2+ is taken back up into the SRTropomyosin blockage restored, contraction ends, muscle fiber relaxes.Na-K pump restores ions to original positions to prepare for next signal.Energy Sources for Contraction ATP is the only energy source that can be used directly to power muscle activity – it must be generated continuouslyStored ATP in working muscles is depleted in ~ 6 seconds.3 main factors affect the type of respiration that will occur:__________________________________________________________________________________________________________________________________________________________________Three pathways that regenerate ATP for musclesDirect phosphorylation of CPAnaerobic respiration(cytoplasm)Aerobic respiration(mitochondria)Energy sourceCreatine PhosphateHigh energy molecule found only in muscle fibersGlucose(only glycolysis used)Glucose, fatty acids (resting/slowly contracting muscles), amino acids (if no glucose/fatty acids available)Oxygen useNoneCP + ADP creatine + ATPNoneRequiredGlucose + oxygen Products1 ATP per CP, creatine2 ATP per glucose, lactic acid~36 ATP per glucose, CO2, H2ODuration of energy15-20 seconds30-60 secondshoursActivitiesBrief maximum power surge:Weightlifting, diving, sprintingMore sustained-less vigorous as O2 depletes Endurance rather than power activities: Marathon, joggingSpeed &efficiencyVery fast, very reversible, easily replenished when muscle are inactive2 ? x faster than aerobic, not as efficient, Slower, requires continuous delivery of oxygen & nutrients to muscle BUT most efficientOxygen Debt , Muscle Fatigue & Heat ProductionOxygen debt is the ________________ amount of oxygen that must be taken into the body to provide for these restorative processesDifference between amount of oxygen needed for totally aerobic respiration during muscle activity AND the amount that is actually used.All ____________________ sources of ATP used during muscle activity contribute to this debtRepaid by rapid, deep breathing (__________________________ - triggered by change in pH from lactic acid) after exertion is endedBreathing pure oxygen does not help recovery time – oxygen has to have time to get to the muscles that require it. There are limitations due to your ______________________ and __________________________ systems.Working your muscles, heart, lungs, etc out on a regular basis increases your efficiencyThings like smoking, poor nutrition, too much sugar, etc. decreases your efficiencyMuscle FatiguePhysiologicalunable to contract even though stimulatedcan be caused by _____________ acid buildup, lack of oxygen in muscle cells to produce ATP, ionic imbalances (Na-K pump)(active transport)when no ATP is available, ___________________ will occur (no ATP = no cross bridge release) psychological — voluntarily discontinuing activity Isometric vs. isotonic contractionsIsotonic (same ________________) contractionsMyofilaments are able to slide past each other during contractionsThe muscle shortens & movement occursConcentric: ____________________________________________Eccentric: _____________________________________________Isometric (same ____________________) contractionsTension in the muscles increasesThe muscle does not shorten & no movement occurs – Resistance exercisesMost movements involve both types of activityMuscle Fiber Types________________, ______________________ and ____________________ of muscle contraction are affected by several factors. A main factor is fiber type:Types of muscle fibers are ______________________ determined. Muscles are a mixture of fibers but different muscles will have different ratios of the types. Fiber Types: Fast twitch fatigable muscle (White meat)Slow twitch fatigue resistant (Dark meat)Discuss why chicken/turkey breast meat is white meat while dove/duck breast meat is dark meat.Skeletal Muscle Actions (tie in to Physics – aka Biomechanics)Muscles exert force by use of lever action. Bones act as levers for muscles to pull on. Each type of lever has advantages and disadvantages in either the _____________ required to move the body part or the ______________ that the body part can be moved or the _____________of the motion.Differences in the positioning of the fulcrum. load, and effort modify muscle activity with respect to:speed of contractiondirection of motionrange of motion (ROM)Strength - weight that can be liftedTerms to UnderstandFulcrum – fixed point - __________________Effort – applied force – provided by ___________________________Load – resistance objects – bone, overlying tissues, & other objects you are trying to moveAs an athlete or trainer: Understanding lever action, angles and position, and muscle fiber direction is extremely important:To maximize the effectiveness of your work outs (work smarter, not harder)To prevent injuryTypes of LeversFirst class leverFulcrum is in the middle The main advantage is the _____________________________________ of the force – force exerted is equal to force liftedExample: hyperextension of neckSecond class leverLoad is in the middle _____________ common in the bodyThe main advantage is __________________________ of effort force (strength) – force exerted is less than force liftedLevers of strength BUT Range of motion is sacrificedExample: Standing on your toes (contraction of calf muscle) lifts your whole body but only a small distanceThird class leverEffort is in the middle ______________common in the bodyThe main advantage is increase in _________________ Strength is sacrificed and speed is gainedThe 5 Golden Rules of Skeletal Muscle Activity All muscles cross at least ______ jointThe bulk of the muscle typically lies ______________________ to the joint crossedMuscles are attached to at least two points__________________ – attachment to the immovable or less movable bone__________________ – attachment to the movable boneMuscles can only __________, they never _________During contraction, the muscle __________________ moves toward the __________Muscle InteractionsAgonistPrime MoverSynergistFixatorAntagonistEXTRA INFORMATION on Building Muscle MassIn order to work a muscle effectively & to minimize risk of injury, there are factors that must be considered. Number of reps and amount of weight depends on purpose of exercise (building vs. toning).Type of joint involved in motionsDirection of muscle fibers (contained in fascicle)Anatomy of the muscleAngles of body partsFascicle arrangement Parallel (fusiform)- best for fast and large movements & range of motion - Longer muscle fibers along muscle axis = greater range of motion - Parallel fascicle arrangement gives greatest ___________Convergent – movement of ________________areasUnipennate - see bipennate infoBipennate - shorten very little but very powerful so best for _______________ - Power: depends on # of Muscle fibers- Greater # = greater powerCircular – open and close4572082550Letters on diagrams matched to info above!00Letters on diagrams matched to info above!Muscle Man Diagrams Study Sheet – Place the numbers on the diagram next to the correct muscle – Anterior & Posterior muscles are all in this same list. A (2) means they show up on both diagrams.Adductors (2)Biceps brachiiBiceps femorisDeltoid (2)External oblique (2)Fibularis longusFrontalisGastrocnemiusGluteus maximusGluteus mediusGracilisLatissimus dorsiMasseterOrbicularis oculiOrbicularis orisPectoralis majorRectus abdominusRectus femorisSartoriusSemitendinosusSoleusSternocleidomastoidTemporalisTibialis anteriorTransversus abdominusTrapeziusTriceps brachiiVastus lateralisVastus medialisZygomaticus Review: Synovial joint movements Angular - increase/decrease angleFlexion and ExtensionPlantar flexion and DorsiflexionHyperextension Abduction and AdductionCircumductionRotation – rotation around a long axis (twisting motion) Medial and LateralArms onlyA. Supination and PronationFeet OnlyA. Inversion and EversionOthersA. Protraction and RetractionB. Elevation and Depression ................
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