1. Epithelial Tissue Page 78 - 81 1

2. Characteristics  Fit closely together to form continuous sheets.  Has an apical surface which is a free surface that is exposed to the body’s exterior or to the cavity of an internal organ.  Has a basement membrane which is where the lower surface is attached.  No blood supply or avascular.  Can regenerate themselves easily. 2

3. Classification of Epithelium Arrangement  Simple – one layer of cells  Stratified – more than one cell layer Shape  Squamous – flattened  Cuboidal – cube- shaped like dice  Columnar – shaped like columns 3

4. Types of Simple Epithelial Cells  Simple squamous  Simple cuboidal  Simple columnar  Pseudostratified columnar 4

5. Simple Squamous Epithelium  Single layer of thin squamous cells  Lines air sacs of lungs, walls of capillaries and forms the serous membranes 5

6. Squamous Epithelium 6

7. Simple Cuboidal Epithelium  Single layer of cuboidal cells  Found in salivary glands and pancreas 7

8. Simple Cuboidal Epithelium 8

9. Simple Columnar Epithelium  Single layer of tall cells  Goblet cells (produce a lubricating mucus)are often present  Lines entire digestive tract from stomach to anus 9

10. Simple Columnar Epithelium 10

11. Pseudostratified Columnar  Single layer of columnar cell with different heights giving it a multiple layer look.  Goble cell often present  Cells found in the respiratory tract have cilia (ciliated). 11

12. Pseudostratified Columnar 12

13. Types of Stratified Epithelia  Stratified squamous  Stratified cuboidal  transitional 13

14. Stratified Squamous Epithelium  Several layers of squamous cells with either cuboidal or columnar cells near the basement membrane.  Found in the esophagus, mouth, and outer portion of the skin. 14

15. Stratified Squamous Epithelium 15

16. Stratified Cuboidal & Stratified Columnar Epithelia  Rare  Found mainly in the ducts of large glands 16

17. Stratified Cuboidal & Stratified Columnar Epithelia 17

18. Transitional Epithelium  Highly modified, stratified squamous epithelium found in the bladder, ureters, and part of urethra.  Cells change shape to adapt to considerable stretching. 18

19. Transitional Epithelia 19

20. Glandular Epithelium  Endocrine glands  Has no connection to the surface – ductless glands  Ex. Thyroid, adrenal, pituitary  Exocrine glands  Secretions empty through the ducts to the epithelial surface  Ex. Sweat and oil glands (external surface), liver and pancreas (internal surface) 20