1. March 3, 2017
Blood Vessels

2. Types of Blood Vessels

3. Blood Vessel Tunics
All vessels except capillaries have three layers, or tunics
Capillaries have a single layer of epithelial cells

4. Comparison of blood vessels
What are the differences? How do they relate to function?
Veins also have valves and are flexible

5. Blood vessel micrograph
What is a? What is b? How do you know? B A

6. How does blood return to the heart?
Muscular pump Respiratory pump
Describe the action of these pumps in 1-2 sentences

7. Capillary Bed
What is the difference between the vascular shunt and true capillaries?
What is the function of precapillary sphincters?

8. Capillary Exchange
Capillary exchange is the movement of substances (water, gases, nutrients, wastes, etc.) between capillaries and the interstitial fluid of tissues
Capillaries have special features which increase their permeability:
Intercellular clefts:
spaces between cells
Fenestrations:
very thin membrane-
covered spots, or pores

9. Capillary Exchange
Capillary exchange is the movement of substances (water, gases, nutrients, wastes, etc.)
Capillaries have special features which increase their permeability:
Intercellular clefts:
spaces between cells
Fenestrations:
very thin membrane
-covered spots, or
pores
Clefts and fenestrations are most important for the diffusion of what kinds of substances?
Water, and other lipid-insoluble substances
What can get through without their help?
O2, CO2, fats

10. Capillary Exchange
Capillary exchange is the movement of substances (water, gases, nutrients, wastes, etc.)
Capillaries have special features which increase their permeability:
Intercellular clefts:
spaces between cells
Fenestrations:
very thin membrane
-covered spots, or
pores
What type of capillaries don’t have fenestrations or intercellular clefts?
Capillaries in the brain – work with astrocytes to form blood-brain barrier

11. Capillary Exchange
Differences in pressure in blood pressure and osmotic pressure help fluids move out of capillaries at the arterial end and into capillaries at venous end.
Watch me!
oncotic pressure – osmotic pressure due to proteins such as albumin; hydrostatic is more like fluid pressure

12. Closure
Explain the statement: “All other blood vessels exist to service the capillaries” How does what we did today relate to our unit question?

13. Exit Ticket
Describe the structure of a capillary and explain how it facilitates it’s function. (2 pts)
Describe 2 differences in the structure of arteries and veins and explain how these differences facilitate their functions. (4 pts)