Los Angeles Mission College



HUMAN HISTOLOGY

IMPORTANT THINGS TO ASK YOURSELF WHEN LOOKING AT & STUDYING TISSUES

1. What does it look like?

2. What is the name (be specific)

3. Where is it found?

4. What is (are) the name(s) of any special cell(s)?

5. What is (are) the name(s) of any special structure(s)?

6. ALL of the above may not apply to ALL of the tissues studied.

CONNECTIVE TISSUES

1. Blood

2. Adipose

3. Areolar connective tissue

4. Reticular connective tissue

5. DWFCT (regular & irregular)

6. Cartilage

(hyaline, fibrocartilage. elastic)

7. Compact bone

EPITHELIAL TISSUES

1. Simple squamous epithelium

2. Simple cuboidal epithelium

3. Simple columnar epithelium

4. PSCCE

5. Transitional epithelium

6. Stratified squamous epithelium

a. keratinized (K)

b. non-keratinized (NK)

MUSCLE

1. Skeletal (teased & diseased)

2. Cardiac

3. Smooth

NERVE

1. Cerebral cortex

2. Giant multipolar neuron

3. Meissner's corpuscle (demo)

4. Pacinian corpuscle (demo)

5. Node of Ranvier (demo)

6. Neuromuscular junction (demo)

MITOSIS

1. Prophase

2. Metaphase

3. Anaphase

4. Telophase

SKIN (as an organ)

1. Epidermis

a. stratified squamous epidermis - K

b. stratum corneum

c. stratum basale {also s. germinativum}

2. Dermis

a. dermal papillae

b. DWFCT (main tissue present)

3. Hair Follicle

a. shaft

b. bulb

c. hair papilla

4. Arrector pili muscle

5. Sebaceous gland

6. Eccrine gland

7. Hypodermis

a. adipose

HISTOLOGY

A tissue consists of a group of cells of similar structure and function, along with the nonliving extracellular substance filling spaces between them. Histologists group all (mature, i.e. not embryonic) human tissues into four major categories: EPITHELIAL, CONNECTIVE, MUSCULAR, and NERVOUS.

You will be expected to accomplish the following: (I) learn to recognize and name the specific types of these four classes of tissues when viewed through a microscope; (ii) name any or all of the structures associated with these tissues; (iii) identify and name the various cells; (iv) name examples of organs or body parts in which these specific tissues may occur; and (v) in some cases describe the function and give the names of specific structures found within the tissue(s).

Following is an outline of the tissues that we will examine through the microscope:

I. CONNECTIVE TISSUE

A. Areolar

B. Adipose

C. Reticular

D. Dense White Fibrous

1. Regular

2. Irregular

E. Cartilage

1. Hyaline Cartilage

2. Fibrocartilage

3. Elastic Cartilage

F. Vascular (blood)

G. Compact Bone

III. MUSCLE TISSUE

A. Skeletal

B. Cardiac

C. Smooth

II. EPITHELIAL TISSUE

A. Simple Squamous

B. Simple Cuboidal

C. Simple Columnar

D. Pseudostratified ciliated columnar {PSCCE}

E. Transitional

F. Stratified Squamous

1. Keratinized

2. Non-Keratinized

IV. NERVE TISSUE

A. Cerebral Cortex

B. Spinal Cord (Giant Multipolar Neuron)

C. Neuromuscular Junction {NMJ} (demo)

D. Sensory Nerve Endings (demo)

1. Meissner(s Corpuscles

2. Pacinian Corpuscles

E. Nodes of Ranvier (demo)

I. CONNECTIVE TISSUE

Connective tissue is one of the most abundant and varied of all types of tissues in the body. Most connective tissues share the important feature of being composed mainly of MATRIX (extracellular substance) with relatively few cells, whereas epithelial tissues are composed mainly of densely packed cells with little matrix. In most cases, it is the matrix that characterizes connective tissues.

Connective tissue matrix includes fibers embedded in an amorphous GROUND SUBSTANCE. The ground substance varies from a fluid consistency to a semisolid gel (solid in bone). Fibers are composed of the structural proteins COLLAGEN and ELASTIN. Fibers of elastin are called ELASTIC FIBERS (sometimes yellow fibers). Fibers of collagen are referred to as COLLAGEN FIBERS, RETICULAR FIBERS, or OSSEIN FIBERS, depending on the tissue in which they occur.

Many different types of cells are associated with connective tissues: FIBROBLASTS {that produce the fibers}, CHONDROBLASTS {immature cartilage cells}, CHONDROCYTES {mature cartilage cells}, OSTEOCYTES {bone cells}, ADIPOCYTES {fat cells}, ERYTHROCYTES {red blood cells}, and LEUKOCYTES {white blood cells}. Other specialized types of cells may be found in connective tissues, but these are beyond the scope of this class.

A. AREOLAR CONNECTIVE TISSUE

Observe on low power a slide labeled AREOLAR TISSUE. This tissue contains long, very thin, thread-like fibers of elastin, a structural protein, called Elastic Fibers. They appear as dark hair-like fibers and provide elasticity to this tissue. Thicker, very pink, non-elastic Collagen Fibers may also be found. Collagen fibers are composed of the most common structural protein in the body ... collagen. Both types of fibers extend in all directions, very much as wind-blown hair appears.

Numerous cells may be seen composed of obvious dark Nuclei surrounded by pale cytoplasm. Fibroblasts are the predominant cell present and actually produce the non-living matrix of this tissue. Macrophages {monocytes} are also present. Many different types of blood cell may occur transiently in this tissue. We will make no attempt to distinguish these cells. This tissue is found around organs, between muscles, and in subcutaneous skin {hypodermis}. Areolar connective tissue can often be seen as a very slimy, grayish film adhering to the underlying muscle of chicken (or any other vertebrate) when the skin is removed.

B. ADIPOSE

Adipose should be observed on both low and high power. Adipocytes {fat cells} appear as large, rather clear cells with very thin cell membranes and a small dark nucleus. They contain only a tiny amount of cytoplasm. Most of the space within the cell membrane is for the storage of Lipids. Generally, when a person gains weight, the adipocytes do not increase in number, but simply enlarge as more lipid is added within the cell membrane. (Infants, if over-nourished, are an exception to increasing the number of adipocytes.)

Adipose tissue has numerous Collagen Fibers running through it; however, the slides used in this class are not prepared in a manner to make these fibers visible. Adipose is found in the hypodermis, around organs, (e.g., the heart and kidneys), within and between muscles, around nerves, and in other places.

C. RETICULAR CONNECTIVE TISSUE

Reticular connective tissue consists of a network of finely branching fibers of collagen called Reticular Fibers. View these on both low and high power. Fibroblasts are the cells that form the reticular {net-like pattern} fibers. This tissue forms the framework of the liver, lymph nodes, spleen, and bone marrow. It is an important tissue of the Reticuloendothelial System {Tissue Macrophage System}, which is instrumental in the defense against microbial invasion.

D. DENSE WHITE FIBROUS CONNECTIVE TISSUE {DWFCT}

Dense white fibrous connective tissue {DWFCT} has a shining white appearance when viewed grossly and is very tough when eaten. (There is also a dense yellow fibrous connective tissue that we will not study).

DWFCT differs from areolar (loose) connective tissue in that it has many more Collagen Fibers and fewer cells. Fibroblasts, although few in number, are the most prevalent cell present. Two major types of this tissue are found in the body. They are described as REGULAR DWFCT and IRREGULAR DWFCT; the difference is determined by the arrangement of the collagen fibers.

Regular DWFCT is found in tendons, ligaments, fasciae, aponeuroses (broad, flat sheet-like tendons), periosteum, and the sclera and cornea of the eye.

You should examine a slide of tendon (the slide MAY be labeled white fibrous tissue). Observe in longitudinal section the thick bundles of pink-staining collagen fibers. The fibroblasts are compressed into thin, wavy purple streaks. (Some slides have cross sections also that you are not responsible for.)

Ligaments connect bone to bone across a moveable joint and are similar to tendons except that they contain many more elastic fibers, thereby exhibiting a greater ability to stretch without tearing.

Fasciae and aponeuroses have the bundles of DWFCT arranged in multiple sheets. In the cornea, each sheet of regular DWFCT is at right angles to the next sheet, as in the layers of plywood.

Irregular DWFCT occurs in the Dermis of the skin and sheaths of nerves. Examine a slide labeled scalp. Look at the dermis and observe the bands of collagen fibers. They appear to be short and extend in all directions, hence the term irregular. This tissue has more elastic fibers than regular DWFCT; therefore, the skin is more elastic than tendons.

E. CARTILAGE

Three types of cartilage occur in the human organism: HYALINE, ELASTIC, and FIBROCARTILAGE. They all share similar structures, but there are sufficient differences to make them recognizable.

Cartilage differs from other connective tissues in that it is avascular (no blood supply). It consists of cells called Chondroblasts, Chondrocytes and extracellular fibers embedded in an amorphous, gel-like matrix. The cavities within the matrix that contain the chondrocytes are called Lacunae.

1. HYALINE CARTILAGE

This is the most abundant type of cartilage. Costal Cartilages attach ribs to the sternum; Articular Cartilages are found at the end of bones in synovial joints. Tracheal Rings in the trachea ("wind pipe") and the Larynx (voice box or "Adam's apple") are other examples of hyaline cartilage. (The epiglottis, part of the larynx, is elastic cartilage.)

Examine a slide of trachea (may be labeled (Hyaline Cartilage( on both low and high power. The trachea is a complex organ composed of many tissues. The cartilage appears as a dense purple area with many cavities (Lacunae) filled by cells (Chondrocytes).

Surrounding the cartilage is a layer called the Perichondrium. Note the cells are very small, flattened, and arranged more closely together than the mature part of the cartilage. Some of these Chondroblasts are capable of becoming chondrocytes and will do so when the cartilage grows. The perichondrium has a blood supply, although the major portion of all cartilage is avascular.

2. ELASTIC CARTILAGE

Elastic cartilage is found in the Auricle or pinna, Eustachian Tube and Epiglottis (part of the larynx). The slide you will examine is from the auricle. The cartilage appears (on low power) as a band of tissue running as a wavy strip through the slide. The same structures found in hyaline cartilage may be seen here also: Perichondrium, Lacunae, Chondroblasts. Chondrocytes, and Matrix. Additionally, numerous thin threads of ELASTIC FIBERS are visible. These fibers may appear as very dark, densely packed threads or as very sparse and hard to distinguish fibers depending on the manner in which the slides were stained. They are responsible for giving this cartilage its pliable characteristic.

3. FIBROCARTILAGE:

This tissue occurs in amphiarthrodic (partially moveable) joints of the vertebrae. These pads of cartilage are called intervertebral discs. It is also present in the pubic symphysis and the sacroiliac joints as well as other places.

This cartilage differs from elastic and hyaline: ( in that it has no perichondrium; ( the chondrocytes tend to occur in horizontal rows rather randomly placed; and there are numerous dense bundles of collagen fibers between the rows of chondrocytes (rather like the bundles of collagen fibers in regular DWFCT as in tendons).

F. BLOOD

Blood has all the criteria necessary for being classified as a tissue; however, it has the unusual feature of lacking the intercellular cementing substance that causes cells in conventional tissues to adhere to one another. Hence, blood is a "liquid" tissue.

Blood cells are very small and must be viewed on high power. The most predominant cell is the Erythrocyte {red blood cell}. It appears as an enucleated reddish cell that seems to resemble a donut. The cell does not actually have a hole in it. Its shape is a biconcave disc because it loses its nucleus during development. The cell "caves in" much as the cheeks of a person who has had all of their teeth pulled. RBC's contain hemoglobin and are responsible for the transportation of oxygen to the tissues. This blood slide is from a person with Sickle-cell Anemia. The occasional Sickled Cell can be seen among the normal erythrocytes. They look somewhat like a football.

Leukocytes are the nucleated cells with a colorless cytoplasm that are referred to as "white" blood cells. Actually, they are not white; they are just not red. The nuclei of these cells stain dark blue or purple. There are numerous types of leukocytes; however, at least 1000 power magnification is necessary to positively identify the many different types. All of these types may be classed in two major groups: Granular Leukocytes {GRANULOCYTES} and Agranular leukocytes {AGRANULOCYTES}. The former have numerous granules in the cytoplasm that are difficult to distinguish even at 430x. Granulocytes are large cells with a three- to five-lobed nucleus. Agranulocytes have a very large spherical nucleus that occupies most of the cell.

Upon very close inspection, numerous TINY purple dots interspersed among the blood cells may be seen. They are Thrombocytes {blood platelets} and are very important in blood clotting.

G. COMPACT BONE

Bone exists as two main types of tissue: Compact Bone, that is found on the surface of bones; and Cancellous Bone, that may be seen as spongy bone on the inner aspects of bones. Mature compact bone is organized into Haversian Systems {Osteons}, each of which exhibits these structures:

a. Haversian Canal: Canal that extends along the length of a bone containing a blood vessel and a nerve.

b. Lacunae: Spaces between the lamellae (layers of matrix) within which the osteocytes occur (mature bone cells).

c. Osteocytes: Mature bone cells trapped in the matrix and occupying the lacunae.

d. Canaliculi: Cytoplasmic processes of osteocytes appearing as tiny hair-like fibers extending from the cell body.

Obtain a slide labeled GROUND BONE and identify the above structures on low power. Note that numerous Haversian systems are visible on the slide. Occasionally, horizontal canals may be seen connecting two Haversian canals. These are called Volkmann's Canals (Not all slides will have a Volkmann(s canal ... be sure to look at your neighbor(s slide).

Bone matrix consists of Ossein Fibers (composed of collagen) embedded in mineralized (calcium salts) ground substance. The protein fibers are not distinguishable on these slides.

II. EPITHELIAL TISSUES

Epithelium covers body surfaces and organs and lines cavities. Each of the following is an example of epithelial tissue: lining of vagina, outer surface of eardrum, outer surface of eye, covering of uterus, epidermis, lining of aorta, lining of stomach, etc.

All epithelial tissues share certain characteristics: a free border or edge and a basement membrane. They have numerous cells and very little extracellular matrix. An exception to this is the basement membrane which is actually non-living ground substance formed by the underlying connective tissue. Most epithelial tissues are attached to a basement membrane of an underlying connective tissue.

Epithelium is classified and often named according to the number of cell layers and the shape of the cells. If the tissue is one cell thick, it is Simple; if it is more than one cell thick, it is Stratified. Squamous epithelial tissues have flat cells that resemble fried eggs. Cuboidal tissues have cells shaped like a peach, and Columnar tissues are shaped like columns (bananas). Hence, a single layer of flattened cells is called Simple Squamous Epithelium. A single layer of column shaped cells is called Simple Columnar Epithelium, etc.

Within each possible classification of epithelium, the cells may or may not have Cilia on their free border. In human tissues these cilia are generally used to move mucus (and consequently anything trapped in the mucus). Cilia are found, for example, lining the respiratory tract, fallopian tubes, and vas deferens.

A. SIMPLE SQUAMOUS EPITHELIUM

This tissue is found in numerous places: Bowman's capsule of the kidney, lining of alveoli in the lungs, capillary walls, etc. We will use the kidney as an example of this tissue. You should refer to chapter 25 in your textbook and learn the BASIC anatomy of the functional unit of the kidney, namely the NEPHRON. The Glomerulus, Bowman's Capsule, and the Renal Tubule must all be recognized and understood FIRST from diagrams, and only then should you attempt to observe them on the microscope. Each of these nephrons (approx. 1,000,000 in each kidney) are all interwoven with each other. Therefore, when a thin slice of kidney is placed on a microscope slide, one cannot expect to see ANYTHING that resembles the diagram.

Place a prepared slide of KIDNEY on low power. The Glomeruli resemble balls of tissue that are surrounded by a thin white space (Bowman's Space). The glomeruli are numerous and more or less randomly distributed in the Cortex of the kidney. Select a glomerulus and switch to high power. Observe across the space (away from the glomerulus) a thin membrane that is one cell thick. This is a Bowman's Capsule. It totally surrounds the glomerulus but is often difficult to see in its entirety. You may have to look at several glomeruli before you find a good example of a Bowman's capsule. The tissue of which Bowman's Capsule is composed is SIMPLE SQUAMOUS EPITHELIUM.

B. SIMPLE CUBOIDAL EPITHELIUM

The Renal Tubule of the kidney is Simple Cuboidal Epithelium through much of its length. Much of the thyroid gland and the outer covering of the ovary are also Simple Cuboidal Epithelium. Most of the tissue on the kidney slide (exclusive of the glomerulus and Bowman's capsule) is simple cuboidal epithelium. Observe on both low and high power the renal tubules cut in both cross & longitudinal sections.

C. SIMPLE COLUMNAR EPITHELIUM

The lining of the gall bladder, stomach, small intestine, and colon is simple columnar epithelium. In the uterus and oviduct, this same tissue occurs with cilia on the free edge. Notice the nuclei are all in neat rows at the bottom of the cells.

D. PSEUDOSTRATIFIED CILIATED COLUMNAR EPITHELIUM (= PSCCE)

Look on the trachea slide (may also be labeled pseudostratified ciliated columnar epithelium) at the edge of the tissue for PSCCE. The Cilia are visible on high power. Goblet Cells may also be seen. The tissue appears stratified because it has nuclei at various levels in the different cells. Although the nuclei appear stratified, each column-shaped cell is attached to the basement membrane; therefore, this is a tissue exhibiting false stratification (hence the name).

E. TRANSITIONAL EPITHELIUM

This tissue was once considered to represent a transitional form between stratified squamous epithelium and stratified columnar epithelium. The term transitional epithelium persists even though the implication of a change from one type to another is no longer considered appropriate. This type of epithelium is stratified and is most often confused with stratified squamous epithelium non-keratinized (as in the vagina). The distinguishing characteristic is the BALLOON SHAPE of the cells on the free border. (In stratified squamous epithelium, they are flat.) This tissue lines the Urinary Bladder.

F. STRATIFIED SQUAMOUS EPITHELIUM

This tissue consists of multiple layers of cells. The layer next to the underlying connective tissues is cuboidal cells; however, the outermost layer of cells is squamous (flattened). Stratified tissues are always named by the shape of the cell layer at the free border. Two types of this tissue are common in humans:

1. STRATIFIED SQUAMOUS EPITHELIUM

NON-KERATINIZED

Found lining the vagina, esophagus, & oral cavity. The epithelial layer is found at the top of the slide. Notice the cells at the surface are flattened and that distinct nuclei are visible. These cells are continuously shed into the oral cavity. The presence of nuclei is a clear indication that keratinization does not occur in this tissue and is useful in distinguishing from the next tissue you will observe (keratinized stratified squamous epithelium). This lining is much thicker in the mature female than the immature or menopausal adult because of the effect of estrogen.

The thicker layer of tissues below the epithelium consists mainly of connective tissues organized into various structures, glands, blood and lymph vessels, nerves (very few), and two unorganized layers of smooth muscle. Near the vaginal orifice the muscle is skeletal rather then smooth.

2. STRATIFIED SQUAMOUS EPITHELIUM - KERATINIZED

The skin is the largest organ in the body and has three layers: epidermis, dermis, and hypodermis. The Epidermis consists entirely of keratinized stratified squamous epithelium over the entire surface of the body with very little difference except on the palms of the hands and soles of the feet where it is much thicker and devoid of hair follicles. Because of this it is often referred to as thick skin or thin skin.

Examine the scalp slide (thin skin) and note the Epidermis, Dermis, and Hypodermis. The epidermis consists of four distinct layers (five on the palms and soles). The bottom-most layer, termed Stratum Basale, consists of a single row of cells next to the dermis. These cells divide (by mitosis), giving rise to the cell layers above. The outer layer of epidermis, the Stratum Corneum, appears somewhat like flaky pie crust near the surface. The cells formed below have all died and been converted into the protein Keratin. They are constantly shed from all of the body surfaces. If excessive shedding occurs from the scalp, it is called dandruff. People allergic to cats, dogs, horses, etc. are actually allergic to the protein in these cells shed by the animal. The stratum corneum is thicker on the palms and soles, especially where a person has a callus or corn.

III. MUSCLE TISSUE

Three types of muscle tissue occur naturally in humans: Skeletal, Cardiac, and Smooth. You must learn to recognize each type and know where it is located in the body.

A. SKELETAL MUSCLE

Place a slide of Teased skeletal muscle on the microscope at 100X. Teased means the muscle fibers have been separated much as in teasing hair. Look for the individual muscle fibers. Note the numerous Nuclei that appear as dark "jelly beans" along the periphery of the fiber. Alternating pale and dark bands called Striations are visible at both low and high power (ADJUSTMENT of the iris diaphragm is critical to maximize the visibility of this characteristic).

This tissue constitutes the ONLY tissue in the body over which you have DIRECT conscious control. For this reason it is sometimes referred to as VOLUNTARY MUSCLE.

Look also a the slide labeled trichinella. This is a worm (Trichinella spiralis) that is a parasite of skeletal muscle tissue. Only animals that eat meat can have this parasite. How does one get the disease called Trichinosis? What is its life cycle?

B. CARDIAC MUSCLE

This tissue is found only in the heart with a few fibers extending into the ascending aorta. Cardiac muscle fibers extend in different directions in the heart. SEARCH for fibers that have been cut LONGITUDINALLY when looking at the slide on low power.

Note the branching of cardiac muscle fibers. This characteristic is distinctly different from other types of muscle. Striations are difficult to see in this tissue. Adjusting the iris diaphragm on high power may help. Intercalated Discs may be seen as partition-like structures at various intervals along the fibers. These discs may appear as a very clear "break" in the fiber or as a dark band transecting it. (Not all slides show these discs well; therefore, one will be on demonstration.)

C. SMOOTH MUSCLE

Smooth muscle, like cardiac, is involuntary (that is, not under conscious nervous control). Its ubiquitous occurrence in the human body includes the following: wall of the uterus, wall of blood vessels, iris of the eye, muscular layer of the stomach & intestinal walls, skin (arrector pili), etc.

Look at a teased smooth muscle slide to observe individual smooth muscle cells. They are very pale and transparent and may be difficult to locate on the slide. You should only use low power and reduce the light with the iris diaphragm until you locate them. Only after viewing and focusing on low power should you switch to high power.

IV. NERVE TISSUE

We will observe only a few of the many examples of nerve tissue. Two main types of cells will be visible: Neurons and Neuroglial Cells. The neurons conduct the nerve impulses and in a few cases produce materials for secretion. The neuroglia serve many varied and important functions for the neurons.

A. CEREBRAL CORTEX

The Cerebral Cortex of the brain is the thin (approx. 1/4 inch) outer layer of the cerebrum of the brain. The dark brown, pyramid-shaped objects are Pyramidal Neurons. They are important in thinking, interpreting sensory data, and causing movement. Exactly what each neuron does is in part related to its position in the brain.

B. GIANT MULTIPOLAR NEURONS

Giant Multipolar Neurons occur in the gray matter of the spinal cord. They may be seen as large blue cells with a Nucleus that generally has a small dark-staining Nucleolus prominently visible. The cell body of these cells are referred to as the Soma. This slide is made by smearing the tissue on the slide and is therefore very unorganized. (These are the cells destroyed by the polio virus, resulting in paralysis.)

The long cytoplasmic extensions from these cell bodies are axons and dendrites. (In these slides you cannot tell for sure which are axons & which are dendrites, ( the noncommital term Neurite is often used). Interspersed among these Giant Multipolar Neurons are small blue dots, which are actually the nuclei of Neuroglial Cells. Neuroglia are the support cells of the nervous system.

C. NEUROMUSCULAR JUNCTION

The Neuromuscular Junction is the region between the Axon Terminal of a motor nerve and a Skeletal (voluntary) muscle fiber. The Motor End Plate is specialized are of the skeletal muscle fiber just opposite the axon terminal. The neurotransmitter, acetylcholine (ACh), is released from the axon terminal and thereby transmits the nerve stimulus to the muscle chemically rather than electrically.

This is a very important physiological unit of the interface between the nervous system and voluntary skeletal muscle. Many different poisons (strychnine) and medicines (muscle relaxers) may affect its normal function.

View this slide on demonstration only. Make certain you identify the above structures and that you understand the difference between motor end plate and neuromuscular junction. Similar structures are associated with autonomic nervous system and smooth muscle but they are called Visceral Efferent Junctions.

D. SENSORY NERVE ENDINGS:

1. MEISSNER'S CORPUSCLES

Respond to light touch and are located in the Dermal Papillae of the skin. The number of receptors in different parts of the body varies. Finger tips and eyelids have many while the skin on the elbow has few.

2. PACINIAN CORPUSCLES

Resembles a slice of onion (as you might place on a hamburger). These are found DEEP in the Dermis and even in the upper hypodermis. They respond to deep pressure. (They also occur deep within various areas of the body.)

E. NODES OF RANVIER

Small gaps called Nodes of Ranvier occur in the Myelin Sheath, a fatty covering of axons in both the CNS (central nervous system) & PNS (peripheral nervous system). The slide you are viewing on demonstration is taken from a peripheral nerve.

V. Cell Cycle

Look at the whitefish blastula slide. At this early stage it doesn’t matter whether we are looking at fish tissue or human tissue. The slide has several blastulas (balls of cells) on it. Focus on one blastula, then put it on high power so that you can identify individual stages. You will need to be able to recognize the 5 stages of the cell cycle. Refer to p. 92 in the Rust book.

1. Interphase

This is a typical cell. All cells that you have observed so far have been in interphase.

a. The nucleus will have a well-defined nuclear membrane.

b. The nuclear material will be in the form of chromatin (the nucleus will look homogeneous)

2. Prophase

a. There is no nuclear membrane

b. The nuclear material is in the form of chromosomes. They look like little dark spots.

3. Metaphase

a. The chromosomes are lined up in the middle of the cell.

b. You can see spindle fibers stretching across the cell.

4. Anaphase

a. The double-stranded chromosomes have separated and each strand is moving toward the opposite pole of the cell. They may be barely separated or almost to the other side of the cell.

5. Telophase

a. The chromosomes are at the poles.

b. The cleavage furrow is present.

c. The nuclear material is still in the form of chromosomes.

d. There is still no nuclear membrane.

VI. Skin as an Organ

Look at the scalp slide again as an example of the skin as an organ consisting of several types of tissue. You will need to be able to recognize the 3 layers of the skin as well as the following structures. You will need to use high power on the layers of the epidermis. Everything else on the skin you should observe on low power.

1. Epidermis- The epidermis is keratinized stratified squamous epithelium. It will look like a darker purple layer at the top of the slide. Find these layers of the epidermis:

a. Stratum corneum- This is the outermost layer. It is the keratin layer and looks like flaky pie crust.

b. Stratum granulosum- This is a thin layer just under the stratum corneum. This is where keratinization begins, and the cells look “grainy”. The nuclei will be flat.

c. Stratum spinosum- This is the thickest layer of the epidermis. The cells are rounded, but the DO NOT look “spiny”. The nuclei will be rounded.

d. Stratum basale (stratum germinativum)- This is a single layer of cells at the base of the epidermis.

2. Dermis

The dermis is the thickest of the 3 layers of the skin. It consists of irregular dense white fibrous connective tissue. There are also other structures present associated with the skin.

a. Dermal papillae- These are wavy “finger-like” projections of the dermis up into the epidermis.

b. DWFCT- irregular

c. Hair follicle- This is actually an epidermal structure that projects far down into the dermis.

d. Hair shaft- This will look like a non-cellular yellowish structure in the hair follicle.

e. Arrector pili muscle- This is a strip of smooth muscle. Look for a strip of slightly wavy tissue that runs at an angle in the dermis

f. Sebaceous gland- This is an oil gland. The ducts open onto the hair follicle, so it will be close to the base of the hair follicle.

g. Eccrine gland- This is a sweat gland. It is a coiled tubular gland. Look at about the level of the sebaceous glands.

3. Hypodermis

This is the bottom layer of skin. It is made up of adipose and areolar tissue, but we will only see adipose tissue.

SUPERIOR APPENDAGES & PECTORAL GIRDLE

|SCAPULA | |HAND | |HUMERUS |

|acromioclavicular facet | |navicular (scaphoid) | |greater tubercle |

|acromion process | |lunate | |lesser tubercle |

|coracoid process | |triangular (triquetrum) | |lateral tubercular crest |

|scapular notch | |pisiform | |medial tubercular crest |

|glenoid cavity | |greater multangular (trapezium) | |intertubercular groove |

|lateral border | |lesser multangular (trapezoid) | |head |

|superior angle | |capitate | |lateral epicondyle |

|inferior angle | |hamate | |lateral supracondylar ridge |

|medial border | |proximal phalanx | |capitulum |

|supraspinous fossa | |MIDDLE phalanx | |trochlea |

|transverse scapular spine | |distal phalanx (pl.= phalanges) | |medial epicondyle |

|infraspinous fossa | |metacarpals (1-5) | |coronoid fossa |

| | | | |olecranon fossa |

|RADIUS | |ULNA | |anatomical neck |

|head | |olecranon process | |surgical neck |

|neck | |semilunar notch | | |

|radial tuberosity | |coronoid process | | |

|styloid process | |radial notch | |CLAVICLE |

|navicular facet | |head | |acromial portion |

|lunate facet | |styloid process | |sternal portion |

|ulnar notch (facet) | | | | |

| | | | | |

INFERIOR APPENDAGES AND PELVIC GIRDLE

|OS COXA | |FEMUR | |TIBIA |

|anterior superior iliac spine | |head | |lateral condyle |

|anterior inferior iliac spine | |anatomical neck (same as surgical neck) | |medial condyle |

|posterior superior iliac spine | |surgical neck (same as anatomical neck) | |intercondylar tubercles |

|posterior inferior iliac spine | |linea aspera {rough line} | |intercondylar eminence |

|iliac crest | |fovea capitis {pit in head} | |anterior crest |

|body of ilium | |popliteal surface | |medial malleolus |

|greater sciatic notch | |greater trochanter | |tibial tuberosity |

|lesser sciatic notch | |lesser trochanter | | |

|arcuate line | |trochanteric fossa | |FOOT |

|acetabulum | |lateral condyle | |distal phalanx |

|acetabular fossa | |lateral epicondyle | |MIDDLE phalanx |

|ischium | |medial condyle | |proximal phalanx |

|ischial tuberosity | |medial epicondyle | |metatarsals (1-5) |

|ischial spine | |intercondyloid notch | |talus |

|ramus of ischium | |lateral supracondylar ridge | |calcaneus |

|pubis | |medial supracondylar ridge | |navicular |

|superior ramus of pubis | |patellar facet | |first cuneiform |

|inferior ramus of pubis | | | |second cuneiform |

|pubic symphysis | |FIBULA | |third cuneiform |

|obturator foramen | |lateral malleolus | |cuboid |

|auricular surface | | | | |

|obturator groove | | | |PATELLA |

| | | | | |

Following is a list of the bones and their key characteristics. These are the only bones that you must distinguish as right or left:

a. Humerus - capitulum

b. Radius - styloid process

c. Ulna - radial notch

d. Scapula - glenoid cavity

e. Os coxa - acetabulum

f. Femur - greater trochanter

g. Tibia - lateral condyle

VERTEBRAL COLUMN, STERNUM, RIBS

VERTEBRA SACRUM

1. Centrum Sacral hiatus

2. Pedicle Sacral cornu

3. Vertebral foramen Sacral foramen (1-4)

(spinal canal) Medial sacral crest

4. Vertebral arch (posterior arch) Lateral sacral crest

5. Lamina

6. Superior articulating processes RIBS

7. Superior articulating facets Costal tubercle & facet

8. Inferior articulating processes Head

9. Inferior articulating facets Neck

10. Transverse processes

11. Spinous process

12. Intervertebral foramen (notch?) STERNUM

13. Demifacets Manubrium

14. Foramen transversarium Gladiolus

15. Costal facet of transverse process Xiphoid process

16. Atlas (C1)

a. lateral masses b. anterior arch

17. Axis (C2)

a. odontoid process (= dens)

18. Cervical vertebrae (C1 - C7)

19. Thoracic vertebrae (T1 - T12)

20. Lumbar vertebrae (L1 - L5)

20. Sacral vertebrae (S1 - S5) (=sacrum)

21. Coccygeal vertebrae (=coccyx)

BONES OF THE CRANIUM AND FACE

|MANDIBLE | |ETHMOID |

|body | |crista galli |

|mental foramen | |cribriform plate |

|mandibular foramen | |perpendicular plate of ethmoid |

|angle | |nasal conchae (DO NOT TOUCH THEM!!) |

|ramus | | |

|condyloid process | |ZYGOMATIC |

|mandibular condyle | |temporal process |

|mandibular notch | | |

|coronoid process | |BONES W/O STRUCTURES |

|alveolar process | |PALATINE |

| | |PARIETAL |

|MAXILLA | |NASAL |

|infraorbital foramen | |VOMER |

|anterior nasal spine | |LACRIMAL |

|infraorbital margin | |HYOID |

|alveolar process | | |

|median palatine suture | |AUDITORY OSSICLES |

|transverse palatine suture | |MALLEUS |

|incisive foramen | |INCUS |

| | |STAPES |

|FRONTAL | | |

|supraciliary ridge (arch) | |SUTURES |

|supraorbital foramen | |lambdoidal |

|supraorbital margin | |squamosal |

|glabella | |coronal |

| | |sagittal |

|TEMPORAL | | |

|mastoid process | |ORBITAL STRUCTURES |

|zygomatic process | |supraorbital fissure |

|external auditory meatus | |infraorbital fissure |

|mandibular fossa | |optic foramen |

|internal auditory meatus | |lacrimal foramen |

|petrous portion of temporal | | |

|styloid process (often broken) | |FORAMEN |

| | |*carotid |

|OCCIPITAL | |incisive |

|external occipital protuberance | |infraorbital |

|internal occipital protuberance | |*jugular |

|occipital condyles | |*lacerum * These foramen need |

|fossa for cerebrum | |lacrimal need to be found on the |

|fossa for cerebellum | |magnum INFERIOR view of the |

| | |mandibular skull only. |

|SPHENOID | |mental |

|pterygoid processes | |optic *Jesus Christ Loves Olives |

|greater wing of sphenoid | |*ovale |

|lesser wing | |rotundum |

|sella turcica {Turk's saddle} | |stylomastoid |

|anterior & posterior clinoid processes | |supraorbital |

STRUCTURES OF THE SHEEP BRAIN

The brain is divided into three main regions. The FOREBRAIN includes the CEREBRUM, THALAMUS, and HYPOTHALAMUS. The MIDBRAIN consists of the TECTUM and TEGMENTUM. The HINDBRAIN is made up of the CEREBELLUM, PONS VAROLII, and MEDULLA OBLONGATA.

* 1. Sulcus (pl. = sulci)

* 2. Gyrus (pl. = gyri)

* 3. Longitudinal & Transverse fissures

* 4. Cerebrum (2 hemispheres; 4 lobes each)

** 5. Corpus Callosum

** 6. Lateral Ventricle

** 7. Fornix

* 8. CN I Olfactory (nerve)

* 9. Olfactory Tract(nerve vs tract??)

* 10. CN II Optic

* 11. Optic Chiasma

* 12. Optic Tract

** 13. Thalamus

* 14. Hypothalamus (the brain tissue surrounding the 3rd ventricle)

* 15. Mammillary Body (part of the hypothalamus

*** 16. Midbrain

(Tegmentum - floor of midbrain

(Tectum - roof of midbrain

Corpora Quadrigemina:

(Superior Colliculi - vision

(Inferior Colliculi - hearing

* 17. Pineal Body - lies between the superior colliculi

** 18. 3rd ventricle

** 19. 4th ventricle

*** 20. Cerebellum

(Arbor Vitae

***21. Pons Varolii

*** 22. Medulla Oblongata

* Trapezoid Bodies

* Pyramids

These structures are not part of the brain, but are associated with it:

***23. Spinal Cord

** Spinal Canal

** 24. Meninges

Dura Mater (demo)

Arachnoid Mater

Pia Mater

* Locate these structures on the whole brain only.

** Locate these structures on the sagittal sectioned brain only.

*** Locate these structures on the whole brain and the sagittal section.

STRUCTURES OF THE EAR

PINNA {AURICLE} Helix

TRAGUS

TYMPANIC MEMBRANE

EXTERNAL EAR

External Auditory Meatus

External Auditory Canal (cerumen)

MIDDLE EAR

AUDITORY OSSICLES = Malleus, Incus, & Stapes

EUSTACHIAN TUBE

INNER EAR

PETROUS PORTION OF TEMPORAL BONE

INTERNAL AUDITORY MEATUS

SEMICIRCULAR CANALS (DYNAMIC BALANCE)

VESTIBULE (STATIC BALANCE)

COCHLEA (Round window & Oval window)

COCHLEAR HISTOLOGY

SCALA VESTIBULI (perilymph)

SCALA MEDIA {=cochlear duct}

(contains endolymph)

SCALA TYMPANI (perilymph)

BASILAR MEMBRANE

VESTIBULAR MEMBRANE

ORGAN OF CORTI

* Hair Cells

* Tectorial Membrane

PHYSIOLOGY OF VISION

1. Extrinsic skeletal eye muscles associated with movement of the eyeball:

Superior Rectus CN III - Oculomotor Lateral Rectus CN VI - Abducens

Inferior Rectus CN III - Oculomotor Superior Oblique CN IV - Trochlear

Medial Rectus CN III - Oculomotor Inferior Oblique CN III – Oculomotor

2. COW EYE DISSECTION: the following structures must be found on the cow eye:

Pupil Blind spot Anterior cavity

Iris Lens Anterior chamber

Sclera CN II Optic nerve Posterior chamber

Choroid layer Ciliary body (muscle) Posterior cavity

Tapetum lucidum Retina Vitreous humor

Bulbar conjunctiva Postorbital adipose Cornea

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