structure of arteries and veins

Question 1

what are the 3 major layers of a blood vessel?

Answer 1

tunica intima
tunica media
tunica externa (adventitia)

Question 2

what is the innermost layer of a blood vessel?

Answer 2

endothelium of tunica intima

Question 3

what are the 4 layers of tunica intima in order from innermost to outermost?

Answer 3

endothelium (simple squamous)
basement membrane of endothelium
lamina propria (CT layer)
Internal elastic membrane

Question 4

what is the internal elastic membrane?

Answer 4

fenestrated layer of elastic fibers

Question 5

what is the tunica media made of?

Answer 5

smooth muscle cells arranged concentrically

external elastic membrane

Question 6

what is the fn of the tunica media?

Answer 6

vasodilation
vasoconstriction
vascular spasms

Question 7

what is the purpose of vasoconstriction?

Answer 7

decrease bl flow beyond that point (by narrowing)

Question 8

what is the purpose of vasodilation?

Answer 8

increase in blood flow (by increasing diameter)

Question 9

what is the protective fn of the tunica media?

Answer 9

vascular spasms

Question 10

describe the tunica externa

Answer 10

aka tunica adventitia

varies from dense CT nearest vessel to loose CT that merges with the CT of the surrounding tissues

Question 11

where are valves found in the vessels?

Answer 11

in all veins larger than 2 mm in diameter

Question 12

what are the valves of vessels?

Answer 12

folds in the tunica interna that form 2 flaps that overlap and occlude blood flow

Question 13

are you more likely to find more valves in the lower extremities or upper extremities?

Answer 13

lower extermities