1. HISTOLOGY
EPITHELIUM CELLS

2. Stem Cells Early cells that are not programmed yet
As development of the organism occurs, these stem cells become specialized.
RISK: If function of the body rely on specialized cells, if those cells are destroyed or disabled, it could lead to disaster for the organism

3. Primary Tissue Tissue: Cells with the same function and structure.
There are four primary tissues:
Epithelium
Connective
Nervous
Muscle

4. EPITHELIAL TISSUE Specialized Characteristics
Fit closely together to form sheets
Lots of tight junctions
One surface exposed to body’s exterior or cavity
Basement Membrane
Foundation for new cells
Avascular
No blood supply of their own
Depend on Diffusion (Capillaries)
Regenerate Easily

5. Epithelium Classification

6. Simple Squamous Epithelium
“Floor Tiles” Filtration, Diffusion
Serous membranes, O2 and CO2 Diffusion, Capillaries

7. Simple Squamous Epithelium

8. Simple Cuboidal Epithelium
Glands, Ducts, Salivary Glands
One layer of cuboidal cells resting on a basement membrane

9. SIMPLE CUBOIDAL Epithelium

10. Simple Cuboidal Epithelium

11. Simple Columnar Epithelium
Goblet cells produce a lubricating mucus. Digestive Tract, Mucous membranes.

12. Simple Ciliated Columnar Epithelium

13. Pseudostratified Ciliated Epithethium
Respiratory Tract; nuclei appear at different heights

14. Stratified Squamous Epithelium
Abuse/Friction, esophagus, mouth, outer skin

15. Stratified Squamous Epithelium

16. Stratified Squamous Epithelium

17. Stratified Cuboidal Epithelium
Usually found with 2 layers being cuboidal
Ducts of glands

18. Stratified Cuboidal Epithelium

19. Stratified Cuboidal Epithelium

20. Stratified Columnar Epithelium
Ducts of large glands, basal cells vary in size. RARE

21. Transitional Epithelium
Highly modified, urinary bladder, ureters,

22. Transitional Epithelium