1. TISSUES

2. TISSUE TYPES Four major tissue types Epithelial tissue
Connective tissue
Muscle tissue
Nervous tissue

3. EPITHELIAL TISSUE
Sheets of cells covering body surfaces or lining body cavities
Form boundaries between different environments
e.g., Epidermis of skin separates inside and outside of body
e.g., Epithelium lining urinary bladder separates underlying cells from urine

4. EPITHELIAL TISSUE Many diverse functions Protection Absorption
Filtration
Excretion
Secretion
Sensory reception

5. EPITHELIAL TISSUE Classification According to shape:
Squamous cells: Flattened like fish scales
Cuboidal cells: Cube-shaped
Columnar cells: Column-shaped

6. EPITHELIAL TISSUE Classification according to cell arrangement:
Simple : one layer
Stratified: more than one layer
Simple epithelial
Simple squamous: usually forms membranes
Simple cuboidal: commonly in glands and their ducts
Simple columnar: lines the entire digestive tract
Pseudostratified columnar: mainly functions in absorption and secretion

7. EPITHELIAL TISSUE Stratified epithelial Stratified squamous:
most common stratified epithelial
Is found in sites that receive a good deal of abuse or friction such as the esophagus, mouth and outer skin
Stratified Cuboidal and Columnar:
Found mainly in the ducts of large glands

9. CONNECTIVE TISSUE Found everywhere in the body Four main classes
Most widely distributed primary tissue
Four main classes
Loose connective tissue (Provides a matrix of support and cushing) eg. Adipose tissue
Cartilage
Bone tissue
Blood

10. CONNECTIVE TISSUE Major functions
Binding and support
Protection
Insulation
Transportation
Which of these functions are accomplished by bone and cartilage? Fat? Blood?

11. NERVOUS TISSUE Main component of the nervous system
Brain, spinal cord, and nerves
Regulates and controls body functions
Two main cell types
Neurons
Generate and conduct nerve impulses
Supporting cells
Non-conducting cells that support, insulate, and protect neurons

12. MUSCLE TISSUE Highly cellular Well vascularized
Responsible for most types of body movement
Possess myofilaments
Actin and myosin
Three types
Skeletal muscle
Cardiac muscle
Smooth muscle

13. TISSUE REPAIR Injured cells release growth factors
Stimulate cells to divide and migrate
Two major tissue repair means:
Regeneration
Replacement of destroyed tissue with same type of tissue
Fibrosis
Replacement with fibrous connective tissue (scar tissue)
Type of repair dependent upon
Type of tissue damaged
Severity of injury

14. TISSUE REPAIR
The regenerative capacity of different tissues varies widely
Some tissues regenerate extremely well
e.g., Epithelial, bone, blood-forming tissue
Some tissues have a moderate regenerative capacity
e.g., Smooth muscle, dense regular connective tissue
Some tissues have a weak regenerative capacity
e.g., Skeletal muscle, cartilage
Some tissues have a virtually no functional regenerative capacity
e.g., Cardiac muscle, nervous tissue

15. TISSUE REPAIR
In non-regenerative tissue and severe wounds, damaged tissue is replaced by fibrosis
Resulting scar tissue is strong, but lacks flexibility, elasticity, and function of normal tissue