1. Tissues “Puttin’ cells together”
Chapter 4

2. Tissues: collection of specialized cells
4 tissues types:
1) Epithelial- covers internal and external surfaces as well as glands
Ex: lining of intestines, skin
Cells bound tightly
Apical- free surface
Attached to underlying connective tissue by basement membrane
Avascular- no blood vessels, cell to cell movement
High rate of replacement due to loss/death

3. Functions (student add)
Epithelial continued
Functions (student add)
Physical protection
Control permeability, some impermeable, some selective
Sensation
Specialized secretions
Exocrine- Exo? Examples?
Endocrine- endo? Examples?

4. More epi…How are epithelial cells attached to each other (pg 91)
Tight junction- at outer layer of skin, holds tight, “waterproof”
Gap junctions- embedded proteins with holes allow ions to flow back and forth
Desmosomes- velcro like buttons, strong but not impermeable like tight junction

5. Apical surface (outside)
Microvilli- increase surface area
ex: ?
Cilia- larger than microvilli and beat in unison to move debri
ex: respiratory tract to move dust out

6. Epithelial cell layers
Simple- one layer
Stratified- many layers

7. Epithelial Cell Shapes
Squamous- thin and flat, “fried eggs”
Cuboidal- little hexagons or squares
Columnar- taller than cuboidal, like columns

8. Classifying epithelia based on layers and cell shapes
Layers: simple or stratified (many layers)
3 Cell types:
Squamous- squatty, like fried egg
Cuboidal- cube shaped
Columnar- tall like a column

9. Connective tissue Most abundant by weight
Support, protection, framework
Cells separated by a framework- fibers and a ground substance ( filler that is usually clear, colorless like maple syrup)

10. Connective tissue cell types
Fibroblast- produces protein fibers
Macrophage- can detach and move, scavengers of invaders
Mast cell- usually near blood vessel, release heparin ( blood thinner) or histamine ( inflammatory)

11. Connective tissue fibers- produced by fibroblasts
Collagenous- thick, strong in parallel bundles: ligaments, tendons, white fibers
Elastic- bundles of microfibrils form branched networks: vocal cords, air passages; “yellow fibers”
Reticular – very thin collagenous fibers; highly branched supporting networks; collagen fibers in 3-D network; supports walls of some organs: liver, spleen, lymphatic organs

12. Categories of Connective Tissues
Loose – thin membranes w/fibroblasts, binds skin to underlying organs; fills spaces between muscles
Adipose – stores fat molecules, cushions, insulates, stores energy
Dense – very strong  tendons, ligaments, poor blood supply = slow repair

13. Cat. of connect tissue cont.
Cartilage – rigid connective tissue; indirect blood supply: ends of bones, nose, ears, shock absorbers between vertebrae; framework for bones
Bone – most rigid due to mineral salts (calcium phosphate, calcium carbonate): bone cells are “osteocytes”; arranged in Haversian systems called “osteons”

14. Cat. of connect tissue cont.
Blood – red blood cells, white blood cells, platelets in blood plasma: RBC – gas transport,WBC – fight infection,Platelets – clotting

15. MUSCLE - contractile
Skeletal - attach to bones; voluntary; recognized by striations; multinucleate
Smooth – no striations; involuntary; walls of hollow internal organs: short, spindle-shaped cells w/ single nucleus
Cardiac – only heart; involuntary: striated; end-to-end cells, contract w/out nerve impulse

16. NERVOUS – brain, spinal cord, peripheral nerves
cells are neurons
coordinate, regulate, integrate body functions
neuroglia – supply nutrients by blood vessel connection; cell-to-cell communication