LAB #1: HISTOLOGY

ANATOMY AND PHYSIOLOGY I & II

PART A: EPITHELIAL TISSUE Epithelial tissues are widespread throughout the body. They form the covering of all body surfaces, line body cavities and hollow organs, and are the major tissue in glands. They perform a variety of functions that include protection, secretion, absorption, excretion, filtration, and diffusion.

The cells in epithelial tissue are tightly packed together with very little intercellular matrix. Because the tissues form coverings and linings, the cells have one free surface that is not in contact with other cells. Opposite the free surface, the cells are attached to underlying connective tissue by a non-cellular basement membrane. This membrane is a mixture of carbohydrates and proteins secreted by the epithelial and connective tissue cells.

Directions: For each type of epithelial tissue, draw & label (isolated cells and whole tissue) in the boxed areas.

1. Simple Squamous Epithelial Tissue SKETCH OF TISSUE

a. Name 2 locations in the body this tissue would be found:

*LABEL: NUCLEI*

b. How does this tissue differ in structure from other epithelial tissues? What function(s) does it serve because of it?

2. Simple Cuboidal Epithelial Tissue SKETCH OF TISSUE

a. Where (name 2) in the body would this be found?

*LABEL: NUCLEI & BASEMENT MEMBRANE*

b. Why is the name, “simple cuboidal” appropriate for this tissue?

3. Simple Columnar Epithelial Tissue SKETCH OF TISSUE

a. Where (name 2) would this tissue be found in the body?

*LABEL: GOBLET CELLS*

b. What cell feature or membrane modification is often found in or on this tissue? What function does it serve?

4. Stratified Squamous Epithelial Tissue SKETCH OF TISSUE

a. Name 2 areas of the body this tissue can be found:

b. How does this tissue differ from simple squamous in form AND function?

5. (Stratified) Transitional Epithelial Tissue SKETCH OF TISSUE

a. How does it differ structurally from other stratified tissue?

b. How does its structure fit its function? And thus, where in the body is this tissue located?

PART B: CONNECTIVE TISSUE

This is the most widespread and abundant type of tissue in the human body. Its function is primarily to bind, support, anchor and connect various parts of the body. Although connective tissue exists in a number of forms, all types have three basic structural elements -- cells, fibers and intercellular substance. The specific identity of all three components varies changing the particular nature and function of the tissue. The non-living intercellular material is called the matrix and is composed of the intercellular substance plus the fibres.

1. Areolar Tissue

The fibers of areolar connective tissue are arranged in no particular pattern but run in all directions and form a loose network in the intercellular material. Collagen fibers are predominant. They usually appear as broad pink bands. Some elastic fibers, apparent as thin, dark fibers, are also present The majority of the cellular elements (i.e. fibroblasts, macrophages, leucocytes, etc.) are difficult to distinguish in areolar connective tissue. One cell type, the mast cell, has course, dark-staining granules in the cytoplasm.

a. Describe the appearance of this tissue: SKETCH OF TISSUE

b. What function does it serve in the body?

c. What locations (name 2) is it found in the body?*LABEL: CELLS & FIBERS*

2. Adipose Tissue

These adipose (or fat) cells are characterized by a large internal fat droplet which distends the cell so that the cytoplasm is reduced to a thin layer and the nucleus is displaced to the edge of the cell. These cells may appear singly but are more often present in groups.

SKETCH OF TISSUE

a. Describe its appearance:

b. What function(s) does it serve?

*LABEL: NUCLEUS*

c. Where (name 2) would it be located in the body?

3. Cartilage Tissue

Cartilage is somewhat elastic, pliable, compact type of connective tissue. Most of the skeleton of the mammalian fetus is composed of cartilage. As the fetus ages, the cartilage is gradually replaced by more supportive bone.

SKETCH OF TISSUE

a. Describe the matrix of this tissue:

b. Where in the ADULT human would this be located?

*LABEL: Chondrocytes (cartilage cells)*

4. Bone

Bone is a connective tissue in which the intercellular components are particularly abundant and are organized in a manner, which endows this tissue with great tensile strength and resistance to compression. Despite its great strength and hardness, bone is a dynamic living tissue, which is constantly being renewed and reconstructed throughout life. Bone may be described as compact or spongy depending on its morphological appearance.

The basic functional unit of compact bone is the Haversian system (shown below). They consist of bone (cells) that has been deposited in concentric rings around a Haversian canal that is occupied by blood vessels, nerves, and lymphatics.

SKETCH OF TISSUE

LABEL: Haversian System & Bone Cells

a. What is the scientific name for the bone cells? _____________________

b. How is the matrix of bone different from cartilage?

5. Blood

Blood is considered a connective tissue for two basic reasons: (1) embryologically, it has the same origin as do the other connective tissue types and (2) blood connects the

body systems together bringing the needed oxygen, nutrients, hormones and other signaling molecules, and removing the wastes.

SKETCH OF TISSUEa. Name the 3 types of cells in blood AND describe their functions:

b. What is the liquid matrix of blood called? ________________

PART C: MUSCLE TISSUE

Muscle cells are highly specialized for contraction. Such contraction may result in the movement of the whole body or a portion of it if the muscles are attached to a movable part of the skeleton. If the muscle is located in the wall of a hollow organ, its contraction may cause the contents of the organ to move, e.g. peristaltic movement of material through the digestive tract. Next, 3 types of muscle tissue that have been distinguished on the basis of structural, functional & location differences are:

1. Skeletal (Striated) Muscle

Skeletal muscles form the "flesh"; sometimes referred to as the "red meat" of an animal's body. As their contraction is under conscious control, they are also called voluntary muscles.

A typical skeletal muscle cell is a highly modified, giant, multi-nucleate cell. Each elongate fiber is cylindrical in shape with blunt, rounded ends. The "cross-striped" (striated) appearance of light and dark banding results from the arrangement of myofibrils, protein contractile units, called sarcomeres are embedded in the muscle tissue.

* Examine & locate an area on the slide showing a longitudinal view of parallel skeletal muscle fibers (ie. muscle fibers do NOT join). Note the position of the nuclei and the prominent, regular cross-striations:

SKETCH OF TISSUE

a. What is the function skeletal muscle?

b. Where are the nuclei in skeletal muscle located?

2. Smooth Muscle

Smooth muscle is abundant throughout the internal organs of the body especially in regions such as the digestive tract. As its contraction is not under conscious nervous control, it is referred to as involuntary muscle.

SKETCH OF TISSUE

a. Describe the structure/shape of the smooth muscle fibers (as compared to skeletal muscle):

b. Where is the nucleus in the smooth muscle (as compared to skeletal muscle)?

3. Cardiac Muscle

Cardiac fibers tend to form long chains of cells which branch and intertwine. The junction of one cell with another in a particular chain is known as an intercalated disc and appears as a heavy dark line running across the fiber.

SKETCH OF TISSUE

a. Where is the only place cardiac tissue is located in the body?

b. Name 1 similarity AND 1 difference between cardiac muscle & smooth muscle.

*LABEL: INTERCALATED DISCS

PART D: NERVOUS TISSUEThe major structural and functional "unit" of nervous tissue is the nerve cell or neuron. Each neuron is composed of a cell body containing a nucleus and one or more long cytoplasmic extensions known as fibres. Highly branched fibers, called dendrites, bring impulses toward the cell body, while a single, unbranched fiber, the axon, carries information away from the cell body. The overall length of a neuron, including dendrites, cell body and axon, may vary from less than two centimeters to a meter or more.

a. DRAW a nerve cell (neuron) and LABEL the: axon, dendrites, cell body w/nucleus AND using an arrow, show the direction of nerve conduction along the neuron.

b. What 3 places in the body is nervous tissue concentrated the most?

c. How is nervous tissue different functionally from other types of tissue?

SKETCH OF TISSUE

Examine a slide of multi-polar neurons or a cross-section of a spinal cord or brain. The large cell bodies of the neurons should be evident. The dendrites and axon of a particular neuron are only apparent at their junction with the cell body.

POST-LAB REVIEW -- Histology Name _______________________Anatomy/Physiology Date _____________ Period _____

Diagrams. Identify the specific name of the TISSUE on each histology slide photo:

1. __________________________ 2. _________________________ 3. _________________________

4. __________________________ 5. __________________________ 6. __________________________

Matching. Choose type of tissue that is related to each structure; choices may be used more than once or not at all !

_____ 7. urinary bladder _____ 11. goblet cells a. connective_____ 8. brain _____ 12. intercalated discs b. epithelial_____ 9. heart _____ 13. dendrites c. muscle_____ 10. alveoli (lungs) _____ 14. chondrocytes d. nervous

15-20. With respect to the 3 types of muscle, complete the following table. Included are similarities and differences in structure, function and location.

Characteristic Skeletal Muscle Smooth Muscle Cardiac Muscle

Visible Striations (present/absent)       Do the cells branch? (Y/N)       Position of the nucleus (side/center)       # of nuclei per fiber (multiple/one)       Location in body (be specific)      

Voluntary/Involuntary (vol/invol)