Lecture 23

Question 1

Describe the differences in anatomy of the different blood vessels

Answer 1

arteries highly muscular/elastic (pressure reservoir)
arterioles have variable diameters, well innervated
capillaries are very thin (single layer of epithelial exchange tissue)
veins are elastic, highly distensible (volume reservoir)

Question 2

What determines blood flow

Answer 2

pressure gradient, resistance

Question 3

How does pressure changw

Answer 3

decreases due to friction between cells, between vessel walls and blood

Question 4

how does resistance change

Answer 4

as radius increases, resistance decreases

Question 5

Describe pressure and pressure gradients in the blood vessels

Answer 5

steady decrease in blood pressure

higher gradient in systemic circuit due to more forceful contraction, longer distance travelled

Question 6

how does blood return to the heart

Answer 6

one way valves

skeletal muscle pump

Question 7

Describe blood velocity and CSA trends

Answer 7

inverse, velocity lowest at capillaries and CSA highest to promote exchange

Question 8

How is blood redirected?

Answer 8

capillary sphincters send blood through arteriovenous bypass or metarterioles (for WBC)

Question 9

What are the 3 types of capillaries

Answer 9

continuous = desmosomes/tight junctions
fenestrated = windows
sinusoidal = gaps, large fenestrations