1. Tissues: The living Fabric
Histology!
Tissues: The living Fabric
Definition: groups of cells that are similar in structure and function

2. Target: Describe the 4 main tissues and give an example of each.

3. 4 Types of Tissues : each has many subclasses and varieties

4. And this one! 

5. Body Tissues Four primary types (functional categories) Epithelium
protection /secretion /absorption/ filtration
Connective
support & structure
Nervous
communication & control
Muscle
movement (internal & external)

6. Epithelial Functions
Protection
Sensory
Secretion
Absorption
Excretion

9. Special Characteristics
1. Cellularity- close-packed cells with very little cellular fluid between them.
2. Specialized contacts- adjacent cells are bound together
3. Polarity- all cells have two surfaces
Apical surface- exposed to outer body or internal organ cavity
Basal surface- attached to base or lower side of structure
5. Avascular but innervated- no blood vessels but are supplied by nerve fibers. Receives nutrients from underlying connective tissue
4. Supported by connective tissue- all epithelial sheets rest on connective tissue. Basal and reticular lamina reinforce the epithelial sheet to resist tearing and stretching along with filtering what will be allowed to pass through to the epithelial
6. Regeneration- replace lost cells rapidly by cell division

10. Classification of Epithelium
Combination of shape & # of cells is used to name tissues
Shape of cells
Squamous – flattened
Cuboidal – cube-shaped
Columnar – column-like

11. Classification of Epithelium
Number of cell layers
Simple
one layer
found in areas of transport
Stratified
more than one layer
High abrasion areas for protection
Secretory membranes

12. Classification of Epithelium
Pseudostratified
“False” layers
Ciliated (respiratory tract)
Non-ciliated (male urethra)
Transitional
multiple layers of epithelial cells, “hodge-podge”
Found in urinary tract
can look cuboidal until bladder stretches, then looks squamos

14. Location and Function Overview
Epithelial Membranes – line body cavity and are open to exterior , helps waterproof and protect body and lines all closed body systems.
3 types
Mucous membranes
Line body cavities OPEN to the exterior
Example: digestive, respiratory, urogenital
Cutaneous Membranes
Skin
Helps waterproof & protect body
First line of defense in immune system
Serous Membranes
Lines all CLOSED body cavities
Serous fluid located between layers to reduce friction due to organ motion
Glandular epithelium- secrete products into tissues, ducts, or blood.
More on these when we study skin!

16. Connective Tissue Found everywhere in the body!
However, the amount in organs varies, skin is mostly connective tissue but brain has very little.
Main classes:
Fat and fibrous tissue
Cartilage
Bone
Blood
Does much more than connect body parts!
Functions:
Binding and support
Protection
Insulation
Transportation of substances

18. Nervous Tissue
Main component of nervous system (brain, spinal cord, nerves)
Neurons are highly specialized cells that generate and conduct nerve impulses.

20. Muscle Tissue
Highly cellular and well vascularized that are responsible for movement!
Three Types
Skeletal
Cardiac
Smooth