Laboratory 13                                                                                     Zoology 1121
                                   Phylum Chordata (Part II)

Quiz
Histology
This covers:
13-3
14-3

 WebCt  has awesome pictures of the all the tissue slides we did in class.
Go into "student tools" then into "search materials" then in the drop down search box, change it from
        "text" to "all text".  Then use the "week" as a search tool and goto week fourteen.

I. Vertebrate Microanatomy
1. Four Major Groups of Tissues
    a.  Epithelial
    b. Connective
    c. Muscular
    d. Nervous
2. Each one has further breakdowns
3. Epithelial
    a. Simple – found at body surfaces
    b. Stratified – found at sites for protection
4. Connective
    a. Bone – skeletal support and protection
    b. Cartilage – firm yet flexible type support
    c. Blood – for fluid transfer of materials
5. Muscular
    a. Smooth – for slow, sustained contractions (involuntary control)
    b. Skeletal (striated) – for rapid contraction (voluntary control)
    c. Cardiac – for rhythmic contraction of the heart
6. Nervous
    a. Central – coordination of input information
    b. Peripheral – think “pathways” - for the sensory info into the CNS and motor output

II. Epithelial Tissue
1. usually sheet-like layer of cells that covers internal or external surfaces
2. cells are said to have two surfaces
    a. apical – side exposed to the external environment
    b. basal – side attached to other cells (called a basement membrane)
3. There are two main subtypes: simple and stratified
4. easy way to differentiate between two subtypes is dependant on thickness of layer
    a. One layer = simple
    b. More than one = stratified
5.  Simple can be further sub-divided into:
    a. Squamous
    b. Cuboidal
    c. Columnar
6. Squamous –
    a. specialized for diffusion
    b. has very flattened appearance
    c. usually hexagonally flattened
    d. nucleus also seems flattened
    e. line cap beds
7. Cuboidal –
    a. square shaped cells (i.e., polygonal)
    b. round nucleus
    c. for diffusion like squamous but found where more sturdiness is required – like kidneys and thyroid
8. Columnar –
    a . cells are more taller than wide
    b. rounded nuclei located more toward the basal end
    c. even more durable that squamous and cuboidal
    d. found in lining of digestive tract and many glandular structures
    e. sometimes find apical end covered in villi
    f. some secrete mucus and called globlet cells
9. Stratified epithelial cells – composed of more than one layer and do not have any further subdivisions
10. Stratified –
    a. not really specialized for absorption/diffusion, but rather for protection
    b. usually the top layer is of squamous or cuboidal type
    c. lines the mouth

III. Connective Tissue
1. Three main types of this: bone, blood, and cartilage
2. All 3 have a non-living “matrix”
3. Matrix secreted by cells themselves
4. Cartilage –
    a. human trachea or ear or parts of nose
    b. dense, clear bluish background substance in which scattered pockets of cells are arranged more or less in layers
    c. Color is key way to determine
    d. Matrix – is noncellular gooey gel
    e. Chondrocytes – the cartilage producing cells – lie in small cavities called lacunae
    f. Perichondrium – a sheath of dense connective tissue surrounding the cartilage usually with a blood supply
5. Bone –
    a. living bone cells (osteocytes) lie in cavities called lacunae within a matrix
    b. Concentrically arranged osteocytes around a central canal (Haversian Canal)
    c. Blood vessels and nerves run through the Haversian canals
    d. Matrix is hardened by calcium secretions
    e. Smaller lacuna called canalculi
    f . Osteocytes have cytoplasmic extensions that branch into the canalculi
    g. Nutrients and oxygen come trought the Haversain canal through the canalculi and to the osteocytes
    h. Thus, the canalculi are perpendicular to the Haversian Canal
6. Blood –
    a. tissue cells suspended in a fluid matrix, unlike the hardened matrix of bone or gel-like matrix of cartilage
    b. Liquid matrix in blood called plasma
    c. Supports many different types of cells
        1. erythrocytes – aka, RBCs b/c red discs
        2. leukocytes – aka, WBCs b/c stain purplish white
        3. Platelets – hard to see about 1/100th size of RBCs

IV. Muscular Tissue
1. Specialized tissue for movement
2. Also for organs of body
3. Muscles only pull (contract) they cannot push
4. Ex, Skeletal muscles usually work in antagonist alignment
    a. one pulls one way, another pulls it back
5. three types:
    a. skeletal
    b. smooth
    c. cardiac
6. Skeletal Muscle
    a. made up of thousands of fibers
    b. each fiber made up of thousand of fibrils
    c. distinct striated appearance because fiber arranged in parallel
    d. each fibril is subdivided into sarcomeres
    e. each sarcomeres subdivided into filaments
    f. many nuclei located to the side of the cell
7. Smooth Muscle
    a. found in wall of the intestinal tract, in some blood vessels, walls of uterus and bladder
    b. long and thin cells
    c. each cell has a nucleus
    d. within the spindle-shaped cells is a single type of thin filament
8. Cardiac Muscle
    a. heart muscle
    b. whereas skeletal muscle are elongated, cardiac muscle is  more compact
    c. cells are NOT aligned end-to-end
    d. form a webbed network
    e. dark bands between the cells called intercalated discs
    f. large numbers of mitochondria

V. Nervous Tissue
1. specialized cells called neurons for conduction of electrical impulses throughout the body
2. quasi-matrix supports the neurons called neuroglia
3. axons covered/wrapped in fat called Schwann Cells

Mammalian Pig - Microanatomy
I.  Digestive System Tissue
1. Smooth muscle surrounds the gut
2. villi – finger-like projections to increase surface area (similar to typhlosole in annelids)
3. villi further break down into microvilli
4. lymph system attached to absorb fatty acids through lacteals

II. Excretory System Tissue
1. Nephron – the functional unit of the kidney
2. Renal corpuscle forms dense ball called a glomerulus
3. Bowman’s capsule – surrounds the glomerulus
4. Convoluted systems
5. Loop of Henle
6. Ascending and descending portions of the loop based on distance to glomerulus
7. Proximal – term used meaning closest to something (in this case the glomerulus)
8. Distal – term used meaning farthest to something (in this case the glomerulus)
9. Notice cortex shell and medulla inside give slide a two-part appearance

III. Reproductive System Tissue
1. Gametogenesis – the formation of either of the sex gametes
2. Takes place in gonadal tissue
3. Primordial germ layer

Ovary Tissue (female)
1. Ovary cells looks like it has many circular holes in it
2. two types of structures visible
        a. ovarian follicles
        b. corpus luteum
3. each ovary carries a number of these
4. Follicle – spherical structure within which the eggs develops
5. Follicle starts as solid mass containing a single large cell called the ova
6. As it grows it becomes hollow and its cells form a central cavity
7. Ova lies adjacent to this cavity and is surrounded by a layer of small cells
8. Hint: cavity plus ova
9. As the egg develops its cavity grows larger
10. When matured, the egg erupts from the follicle
11. After eruption, follicle cells grow and multiply to fill cavity
12. Now this is called a corpus luteum (CL)
13. Both follicle and CL act as endocrine glands and as such discharge hormones
            a. follicle – produces estrogen (for thickening of the uterus’s lining)
            b. CL – secretes progesterone (for further thickening of the uterine lining)
                    - progesterone – means “for gestation”
14. If implantation of a fertilized zygote does not occurs, then CL shrivels and stops secretion and uterine lining is
        sloughed off with a considerable amount of blood in process known as menstruation

Testis (Male)
1. seminiferous tubules – long coiled tubules within which sperm gamestes are produced
2. Two types of cells in seminiferous tubules
a. Spermatagonia – the actual sperm producing cell
b. Sertoli cell – accessory cells that play a nutritive support
3. Sperm cells move toward lumen of tubule as the develop
4. Mature sperm and tails seen in the lumen
5. Embedded within this tissue can be seen the large interstitial cells
6. These cells produce the hormone testosterone

IV. Respiratory System tissue
1. Skip, but look over

VI. Nervous System Tissue
1. Skip but look over

VII. Endocrine Tissue of Pancreas
1. Bulk of this tissue produces digestive enzymes
2. Scattered around the broken tissue are another type of cells called “islets of Langerhans”
3. Islets – highly vascularized and stain different than rest
4. Islets are endocrine in function (rest of tissue is not) and produces two types of hormones used in body
        a. Insulin – control sugar metabolism
        b. Glucagon – also controls sugar metabolism
5. Diabetes Mellitus caused when these Islets are destroyed
 

Important Terms
Skeletal muscle: Sarcromeres, fibers, fibrils, nuclei.
Cardiac muscle: Intercalated discs
Smooth Muscle: single nucleus/cell, spindle shaped.

Skeletal --    Bone: osteocyte, canaliculi, central (Haversian) canal, lacuna.
                    Cartilage: Chondrocyte, lacuna, cartilagenous matrix.

Circulatory System -- R/L atrium, R/L ventricle, aortic arch, pulmonary, vein, artery, arterioles, capillaries, blood.

Digestive System -- mouth, pharynx, esophagus, stomach, duodenum, colon, cecum, jejuno-ileum, rectum, liver,
                                gall bladder, pancreas, villi, smooth muscle layers, epithelium, pancreatic digestive enzymes,
                                bile, gastric gland.

Excretory System -- Kidney, bladder, Ureter, Urethra, Nephron, glomerulus, bowmans's capsule, tubules, loop of Henle.

Reproductive System  -- Testis: seminiferous tubule, lumen of tubule, sertoli cells, developing sperm testosterone.
                                        Ovary: Follicle, mature follicle, corpus luteum, estrogen and progesterone.

Endocrine System  -- Pancreas: islets of langerhans, insulin, glucagon.
                                  Thyroid: Follicle cells, thyroxine, parafollicular cells, calcitonin.