1. Biology II: Unit 3
Tissues & Cancer

2. Tissue Groups of similar cells that perform a specialized function
4 Main Tissue Types:
Epithelial
Connective
Muscle
Nervous

3. Epithelial Tissue Forms protective coverings
Covers organs, inner linings of body cavities, & lines hollow organs
Also function in secretion and absorption
Readily divide & can heal rapidly

4. Epithelial Tissue Always an apical (free) surface that is exposed
Basement membrane- nonliving layer that anchors the epithelial tissue to the connective tissue below

5. Epithelial Tissue Packs tightly to form protective barriers
Outer layer of the skin and mouth

6. Epithelial Tissue is Classified by:
Shape:
Squamous – thin, flat shape
Cuboidal – cube shaped
Columnar – tall, elongated shape
Number of layers:
Simple – single layer
Stratified – 2 or more layers

7. Shape

8. Simple Squamous Epithelium
Fit tight like floor tiles
So thin that substances easily pass through
Lines air sacs (alveoli), capillaries, and blood and lymph vessels

9. Simple Cuboidal Epithelium
Have centrally located, spherical nuclei
Surround ducts, kidney tubules, and ovaries
Secrete glandular products (like hormones, for ex.)

10. Simple Columnar Epithelium
Longer than they are wide
Elongated nuclei
Sometimes ciliated (have cilia to help move fluid along top of tissue layer)
Lines female reproductive tract and digestive tract
Can have microvilli, tiny projections specialized in absorption

11. Pseudostratified Columnar Epi.
Tissue looks layered but is not
Cells can vary in shape and nuclei reach different levels in the cell
Have cilia to sweep away mucus or fluid/debris
Found in the respiratory system

12. Stratified Squamous Epi.
Thick tissue layer where new cells divide near the basement membrane and push the older cells outward, flattening them
Forms the epidermis

13. Stratified Cuboidal Epithelium
Lines larger ducts, providing a thicker tissue layer & more protection
Mammary glands, sweat glands, salivary glands, pancreas, etc.

14. Stratified Columnar Epithelium
Outer layer is columnar cells but the basement layer is cuboidal cells
Found in the male urethra

15. Transitional Epithelium
Changes due to increased tension
Forms the lining of the bladder and urethra
1. Why would these organs need to stretch?
2. Why would it be beneficial if the cells stretched from cuboidal to squamous?

16. Glandular Epithelium
Can be cuboidal or columnar epithelium that specializes in making & secreting molecules into ducts or body fluids
They make up glands
Exocrine glands
Endocrine glands

17. Exocrine Glands
Glands that secrete their products into ducts that open onto surfaces, such as the skin or lining of the digestive tract
Merocrine, Apocrine, & Holocrine Glands

18. Endocrine Glands
Glands that secrete their products into tissues fluid or blood

19. Homework: 5.1 Check your Recall 5.2 Check your Recall 5-7
Make notecards for the types of Epithelial Tissue; Sketch out the tissues on your notecards