1. Tissues

2. Tissue Basics
What is a tissue? Groups of cells working together to perform a function
Four Basic Types of Tissues
Epithelial
Covers surfaces, lines cavities, forms glands
Connective
Protect/support, stores energy, provides immunity
Muscle
Causes movement
Nervous
Detects changes, sends/receives impulses

3. Epithelial Tissue Characteristics
Arranged in closely packed sheets
Singular or multiple layers
Layered
Apical surface (most superficial)
Exposed to outer most layer of body cavities
Lines organs or exterior of body
Lateral surface (cells facing cells)
Basal Layer (deepest layer of cells)
Basement membrane fibers that bind and support
Avascular: Lacking blood vessels
Materials are exchanged by diffusion from connective tissue
Contain a nerve supply
High capacity for renewal

4. Epithelial Tissue Called: Epithelium = singular, Epithelia = plural
Two Types:
Covering and Lining
Outer covering of the skin and internal organs
Lines body cavities and interiors of some systems, blood vessels
Glandular
Makes up the secreting portions of glands
Ex: Sweat glands

5. Basic Epithelia Shapes
Categorized as either:
Simple cells organized in a SINGLE layer
Found where diffusion, osmosis, filtration, secretion, and absorption occur
Stratified cells organized in 2 or more layers
Found where protection is needed and there is often wear and tear

6. Simple Epithelium Squamous= flat cells Cuboidal= cube shaped cells
Important for filtration (kidneys) or diffusion (lungs & capillaries)
Cuboidal= cube shaped cells
Important for secretion and absorption
Columnar= column shaped cells
Important in absorption and secretion of mucus

7. Simple Squamous Epithelium single layer of flat cells

8. Simple Squamous Epithelium single layer of flat cells

9. Simple Cuboidal Epithelium cube shaped cells, rounded nuclei

10. Simple Cuboidal Epithelium cube shaped cells, rounded nuclei

11. Simple Columnar Epithelium May be ciliated or non-ciliated

12. Simple Columnar Epithelium May be ciliated or non-ciliated

13. Simple Columnar Epithelium May be ciliated or non-ciliated

14. Simple Columnar Epithelium May be ciliated or non-ciliated

15. Pseudostratified Columnar appears stratified: nuclei at various levels

16. Pseudostratified Columnar appears stratified: nuclei at various levels