Cells and Tissues

1. Cells and Tissues

2. Body Tissues • Tissues • Groups of cells with similar structure and function • Four primary types • Epithelial tissue (epithelium) • Connective tissue • Muscle tissue • Nervous tissue

3. Epithelial Tissues • Locations • Body coverings & organ linings • Cells fit closely together and often form sheets • Functions • Protection • Absorption • Filtration • Secretion

4. Classification of Epithelia • Number of cell layers • Simple—one layer • Stratified—more than one layer Figure 3.17a

5. Classification of Epithelia • Shape of cells • Squamous • flattened • Cuboidal • cube-shaped • Columnar • column-like Figure 3.17b

6. Simple Epithelia • Simple squamous • Single layer of flat cells • Used for rapid diffusion, forms membranes • Found: Lines lungs (air sacs) & capillaries

7. Simple Epithelia Figure 3.18a

8. Simple Epithelia • Simple cuboidal • Single layer of cube-like cells • Location: Walls/tubules of kidney, lines pancreas, salivary gladns • Fnx: secretes

9. Simple Epithelia Figure 3.18b

10. Simple Epithelia • Simple columnar • Single layer of tall cells • Often includes mucus-producing cells • Found: Lining digestive tract, stomach

11. Simple Epithelia Figure 3.18c

12. Simple Epithelia • Pseudostratified columnar • Single layer, but some cells are shorter than others, some with cilia • Cilia used to push substances across surface • Found: respiratory tract, trachea • May function in absorption or secretion

13. Simple Epithelia Figure 3.18d

14. Stratified Epithelia • Stratified squamous • Found as a protective covering where friction is common • Locations: Skin, Mouth, Esophagus, Vagina

15. Stratified Epithelia Figure 3.18e

16. Stratified Epithelia • Transitional epithelium • Shape of cells depends upon the amount of stretching • Found: Lining of the urinary/bladder

17. Stratified Epithelia Figure 3.18f