1. Histology Study of Tissues

2. Level of Organization 1. Cell level – most basic level of organization in living things 2. Tissue level  Group of similar cells  Perform the same function

3. Level of Organization 3. Organ level – a group of tissues working together 4. Organ System – several organs working together as one unit 5. Organism – an individual that can carry out life processes by means of organ systems

4. Histology – Study of Tissues

5. How do Cells Stick Together? 1.Recognize “like” cells Surface Glycoproteins  95% Carbohydrate  Identity “markers”

7. How do Cells Stick Together? 2. Cell connections – Tight junctions – Desmosomes – Gap junctions

8. Tight Junction Desmosomes Gap Junction

9. Tight Junctions Cells are “sewn” together Prevents passage between cells

10. Desmosomes “Spot- welded” together Prevents Cells from being pulled apart

11. Gap Junctions Tunnel or channel connection Allows transfer of materials between cells

13. Epithelial Tissue Function 1. Protection 2. Lining 3. Absorption

14. Epithelial Tissue Function 4. Filtration 5. Secretion

15. Connective Tissue Function 1. Support 2. Bind

16. Connective Tissue Function 3. Connect 4. Defend

17. Muscle Tissue Function 1. Contraction 2. Movement

18. Nervous Tissue Function 1. Control 2. Receive, integrate, respond

19. Nervous Tissue Function 3. Conduct action potential