1060- Structure and function of blood vessels

Question 1

What are the three outermost layers of blood vessels called ?

Answer 1

Tunica adventitia, tunica media and tunica intima

Question 2

tunica intima

Answer 2

endothelial cells line the inner surface and the basal lamina

Question 3

tunica intima in larger vessels

Answer 3

a subendothelial layer of loose connective tissue and an internal elastic lamina beneath the subendothelial layer.

Question 4

tunica media

Answer 4

concentric layers of helically arranged smooth muscle cells with variable amounts of elastin and proteoglycans

Question 5

tunica adventitia

Answer 5

longitudinally oriented collagen and elastin fibres

Question 6

systole

Answer 6

expansion of the elastic arteries which limits the increase in pressure.

Question 7

diastole

Answer 7

elastic recoil keeps the atrial pressure therefore maintaining the flow and preventing muscle collapse.

Question 8

vasa vasorum

Answer 8

a network of small blood vessels which supply the walls of larger blood vessels

Question 9

describe 2 structures of arterioles and two important functions

Answer 9

1-5 layers of smooth muscle cells . has a very thin adventitia . they constrict or relax to maintain mean arterial blood flow and to alter blood flow through capillaries down stream.

Question 10

formula for the control of cardiac output

Answer 10

heart rate x stroke volume

Question 11

MABP definition

Answer 11

the average pressure in systemic circulation

Question 12

Darcy’s Law

Answer 12

pressure = flow x resistance

Question 13

MABP formula

Answer 13

cardiac output x total peripheral resistance

Question 14

why is regulating MABP a bit of a balancing act

Answer 14

must be maintained within normal limits so not to high otherwise there is the risk of tissue damage , or not too low as it risks the vessels collapsing. However due to metabolic demand regional changes in blood flow are demanded.

Question 15

how does altering arteriolar radius alters TPR and hence MABP

Answer 15

because decreasing the vessel radius can cause relatively large increases in the vessel resistance .

Question 16

name 3 vasoconstrictor stimulators

Answer 16

noradrenaline, angiotensin II and endothelin

Question 17

name 3 vasodialator stimuli

Answer 17

adrenaline , acetylcholine and histamine

Question 18

what kind of receptors do noradrenaline primarily act on ?

Answer 18

alpha- adrenergic receptors.

Question 19

How does the medulla respond to increased MABP

Answer 19

decreases sympathetic and increases parasympathetic , which results in lower peripheral resistance and cardiac output. , which lowers MABP back to normal

Question 20

How does the medulla respond to the reduced MABP ?

Answer 20

by increasing sympathetic and decreasing parasympathetic to raise TRP and CO therefore raising the MABP back to normal

Question 21

What are capillaries surrounded by?

Answer 21

Pericytes

Question 22

Why is blood flow velocity important?

Answer 22

Slowing of blood flow maximizes time available for exchange of substances between blood and interstitial fluid

Question 23

What types of capillary are there ?

Answer 23

Continuous ,discontinuous and fenestrated

Question 24

Continuous capillary structure and where is it found (5) ?

Answer 24

Tight junctions and continuous basal lamina

Found in brain, muscle, thymus, bone and lung

Question 25

Discontinuous

capillary structure and where is it found ?

Answer 25

Large gaps between endothelial cells and discontinuous basal lamina
Found in tissues where there is a need for a close association of blood and surrounding cells (e.g. liver and spleen)

Question 26

Fenestrated capillary structure and where is it found (3) ?

Answer 26

have many fenestrations and a continuous basal lamina , found in intestinal villi , renal and glomerular capillary tissues