This document discusses epithelial tissues. It defines tissue and lists the main categories. Epithelial tissues are covered in detail, including their general features, structural classifications based on cell shape and layers, and major types such as simple squamous epithelium, stratified squamous epithelium, and pseudostratified columnar epithelium. Functions and sample locations are provided for each type. Intercellular junctions and specializations of the cell surface like microvilli and cilia are also described.

1. TISSUES

2. Tissue: A Definition
A group of connected,
interdependent cells that
cooperate to perform a
specific function

3. Categories of Tissue
1. Epithelial Tissue
2. Connective Tissue
3. Muscle Tissue
4. Nervous Tissue

4. Epithelial Tissues
• General Features
Cellular Layer +
Basement
Membrane

5. Epithelial Tissues
• General Features
Cellular Layer + Basement Membrane
No Direct Circulation/Blood Supply
Touch Each Other
Rapid Rate of Cell Reproduction

6. Epithelial Tissues
• Structural Classification
Cell Shapes

7. Columnar
Cuboidal
Squamous

8. Epithelial Tissues
• Structural Classification
Cell Shapes
Cell Layers

9. Simple

10. Stratified

11. Epithelial Tissues
• Major Types

12. Simple Squamous Epithelium

14. Simple Squamous Epithelium
Function: Exchange
Sample Locations:
Alveoli, capillaries

15. Stratified Squamous Epithelium

16. Stratified Squamous Epithelium
Function: Protection
Sample Locations: Skin, Mouth, Repro tracts

17. Simple Cuboidal Epithelium
Function: Absorption or Secretion
Sample Locations: Kidney, Hormone Glands

18. Simple Columnar Epithelium
Function: Absorption (or Secretion)
Sample Location: Digestive Tract
Microvilli

19. Simple Columnar
Note goblet cells

20. Pseudostratified Columnar Epithelium
Note cilia

21. Pseudostratified Columnar Epithelium

22. Pseudostratified Columnar Epithelium
Function: Absorption, Secretion, Movement
Sample Locations: Respiratory & Repro Ducts

23. Transitional Epithelium
Function: Stretchability
Sample Location: Urinary Bladder

24. What kind of tissue is this?

25. Epithelium cont.
• Epithelium that lines cavities sits on lamina
propria.
– Supports epithelium
– Binds epithelium to other tissue
– Provides nutrition
• Sides of cells are named
– Basal
– Apical (free)
– Lateral

26. Basal Lamina-Lamina Propria

27. Intercellular
Junctions
Belts that circle cell.
ZO (tight junction) acts as
barrier.
ZA provides for adhesion of
one cell to another
Spots
Des is like a spot welding.
Gap allows passage of
chemical for communication.

28. Gap
Junction

29. Specializations of Cell Surface
• Microvilli
– Found mainly on absorptive cells
– Brush border, 1 high
• Cilia / flagella
– Cylindrical, motile structures, 5-10 high
– Contain microtubules
– Basal bodies

30. Microvilli
Apical region of an intestinal epithelial cell seen with TEM. Filaments
that constitute the core of the microvilli are clearly seen. An extracellular
cell coat (glycocalyx) is bound to the plasmalemma of the microvilli.
x45,000.

31. Cilia