1. Objectives: Name the four major tissue types and their subcategories
Explain how each type of tissue is classified
Relate each types structure to the function it performs in the body
What are the common characteristics for each tissue type

2. Jigsaw activity
Aces: Explain classification of Epithelial tissue (page 78-79)
Kings: Characteristics of Epithelial tissue
Queens: Simple Epithelial (subcategories, function and location)
Jacks: Stratified Epithelial (subcategories, function and location)
Tens: Glandular Epithelium (subcategories, function and location)

3. Body Tissues Cells are specialized for particular functions Tissues
Groups of cells with similar structure and function
Four primary types
Epithelium
Connective tissue
Nervous tissue
Muscle
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4. Epithelial Tissues Found in different areas Functions Body coverings
Body linings
Glandular tissue
Functions
Protection
Absorption
Filtration
Secretion
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5. Epithelium Characteristics
Cells fit closely together (Sheet Like)
Tissue layer always has one free surface
The lower surface is bound by a basement membrane
Avascular (have no blood supply)
Regenerate easily if well nourished
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6. Classification of Epithelium
Number of cell layers
Simple – one layer
Stratified – more than one layer
Figure 3.16a
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7. Classification of Epithelium
Shape of cells
Squamous – flattened
Cuboidal – cube-shaped
Columnar – column-like
Figure 3.16b
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8. Simple Epithelium Simple squamous Single layer of flat cells
Usually forms membranes
Lines body cavities
Lines lungs and capillaries
Figure 3.17a
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9. Squamous The epithelium is a single layer of flat, or squamous, cells.
The peripheral cytoplasm of each cell is so attenuated that it is usually not resolvable; the nucleus is usually the only cellular structure visible.
The nucleus usually has a flattened appearance (sometimes spherical), and, due to the width of the cells, nuclei of adjacent cells are usually separated by a distance of many nuclear diameters.
The cells' surfaces are void of specialized surface structures, such as cilia or microvilli.

10. Basement membrane

11. Apical surface
Basement membrane

12. Simple Epithelium Simple cuboidal Single layer of cube-like cells
Common in glands and their ducts
Forms walls of kidney tubules
Covers the ovaries
Figure 3.17b
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13. Cuboidal
This epithelium consists of a single layer of cuboidal cells resting on an undetectable basement membrane.
The height of each epithelial cell is nearly equal to the width of the cell.
The cells are tightly packed, forming a continuous sheet of cells that effectively forms the wall of a kidney tubule.
The nucleus is spherical and sits at the near-center of the cell.
The nuclei of adjacent cells are relatively close together, certainly closer than in a simple squamous epithelium, and are aligned in a single row.

16. Simple Epithelium Simple columnar Single layer of tall cells
Often includes goblet cells, which produce mucus
Lines digestive tract
Figure 3.17c
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17. Cuboidal
The epithelium consists of a single layer of columnar cells (the cells' height is significantly greater then their width) resting on an undetectable basement membrane.
The cells are tightly packed, forming a continuous sheet of cells that effectively forms the protective lining of the stomach.
The nucleus is generally ovoid and sits at the lower to mid-portion of the cell.
Because the width of the cell is relatively narrow, the nuclei of adjacent cells are relatively close together and are aligned in a single row.

19. Fig. 2. Mammalian stomach (H & E).
Lu, stomach lumen
LuS, lumenal surface.
Epi, simple secretory columnar epithelium

20. Simple Epithelium Pseudostratified
Single layer, but some cells are shorter than others
Often looks like a double cell layer
Sometimes ciliated, such as in the respiratory tract
May function in absorption or secretion
Figure 3.17d
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21. Pseudostratified
The nuclei staggered, while not obvious, all the epithelial cells in this membrane rest on the basement membrane, but they vary in height - all do not reach the apical surface. This contributes to the staggered locations of the nuclei.
Note the ciliated border of the columnar cells. Cilia are relatively flexible, motile hair-like surface projections. The cilia of the respiratory epithelium beat constantly toward the pharynx and nasal passages, creating a continuous flow of mucus in that direction.
Note the presence of goblet cells. While individual goblet cells are seldomly distinct, a mucus cup can occasiionally be seen. Tracheal goblet cells secret mucus over the surface of the epithelium to prevent dessication and to trap air-borne microscopic particulates, thus cleansing air as it passes to the lung alveoli.

23. Stratified Epithelium
Stratified squamous
Cells at the free edge are flattened
Found as a protective covering where friction is common
Locations
Skin
Mouth
Esophagus
Figure 3.17e
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25. Stratified Epithelium
Stratified cuboidal
(RARE) a) When found, you see it as two layers of cuboidal cells b) Ducts (sweat glands, mammary glands).
Stratified columnar (very limited in distribution)
*Present in Large ducts of some glands* Pharynx, male urethra, and lining some glandular ducts.
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26. Stratified Epithelium
Transitional epithelium
Shape of cells depends upon the amount of stretching
Lines organs of the urinary system (Ureters, urinary bladder, part of the urethra)
Figure 3.17f
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28. Glandular Epithelium
Gland – one or more cells that secretes a particular product
Two major gland types
Endocrine gland
Ductless
Secretions are hormones
Exocrine gland
Empty through ducts to the epithelial surface
Include sweat and oil glands
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