Circulatory Vasculature

Question 1

what are the 3 general layers of vasculature?

Answer 1

tunica intima- inner most layer- internal elastic lamina- basement layer of intima- tunica media- circularly arranged smooth muscle and elastic fiber- external elastic lamina- tunica adventitia- mostly CT that blends into the surrounding CT. vaso vasorum and nervi vascularis (blood and nerve innervation of smooth muscle)

Question 2

describe large arteries

Answer 2

found close to heart with large medias and extensive elastic fibers to allow for pressure oscillations

Question 3

describe muscular arteries

Answer 3

downstream of large arteries, again with huge medias but far fewer elastic fibers. can have 4-40 layers of muscle

Question 4

describe arterioles

Answer 4

arterioles are the larges of the microcirculation. they have 1-4 layers of muscle in their media. despite their size, their combined contribution is the largest to TPR.

Question 5

capillaries

Answer 5

only 9-12 um. there are 3 subtypes

Question 6

name and describe the 3 types of capillaries

Answer 6

continuous- uninterrupted epithelium. nutrient exchange is diffusion and pinocytotic. found more in skeletal muscle. fenestrated- small pores w/ diaphragm. found in areas like kidneys and small intestine where exchange of larger materials occurs. sinusoid/discontinuous- large gaps w/ no diaphragm and discontinuous epithelia- bone marrow, liver, spleen, lymph, and endocrine glands

Question 7

post capillary venules

Answer 7

only slightly larger than capillaries, significant exchange still occurs here. covered in contractile pericytes, often found associated with arterioles. WBCs leave here.

Question 8

functions of epithelial cells lining vasculature

Answer 8

activation and inactivation of substances/lipolysis/production of vasoactive factors/antithrombogenic/inflammation

Question 9

what is the affect of nitric oxide? endothelin?

Answer 9

nitric oxide- dilator. endothelin- vasoconstrict

Question 10

characteristics of large veins

Answer 10

thick tunica adventita. increasing elastic fibers. longitudinal smooth fibers arranged in tunica adventita. most veins have bicuspid valves

Question 11

what are the tunica equivalents in the heart?

Answer 11

endocardium, myocardium, and endocardium

Question 12

where are the purkinje fibers found?

Answer 12

myocardium

Question 13

characteristics of lymph

Answer 13

dont have the 3 layers. very thin and incomplete endothelial layers. also contain valves