systemic circulation

Question 1

in blood vessels, as volume increases what does pressure do?

Answer 1

increase

Question 2

what is the compliance equation?

Answer 2

C= change in volume/change in transmural pressure

Question 3

what is the elastance equation?

Answer 3

E= 1/C

= change in transmural pressure/change in volume

Question 4

describe the structure of an artery

Answer 4

very round, thick wall, a lot of collagen, a lot of extracellular material

Question 5

describe the structure of a vein

Answer 5

“floppy”, thin walled

Question 6

can compliance be homeostatically regulated?

Answer 6

NO

Question 7

about what is the compliance for the aorta?

Answer 7

~2mL/mmHg

Question 8

about what is the compliance for veins?

Answer 8

100 mL/mmHg

Question 9

arteries or veins, what does this statement describe

“small pressure changes have large volume changes”

Answer 9

describing the high compliance of veins

Question 10

how much more volume do veins have than arteries?

Answer 10

about 3x

Question 11

how much more distensible are veins than arteries?

Answer 11

8x

Question 12

when will blood pressure drop to zero?

Answer 12

if blood volume dorps below 400 mL

Question 13

veins or arteries; which has lower pressure?

Answer 13

veins

Question 14

veins or arteries; which has higher blood volume?

Answer 14

veins

Question 15

what happens to compliance as a person ages?

Answer 15

it decreases

Question 16

what is 1 consequence of reduced compliance?

Answer 16

the heart must work harder to pump blood through stiffer vessels

Question 17

describe the windkessel effect

Answer 17

the aorta, pulmonary artery and their major branches store a volume of blood (and elastic energy) during systole and then deliver the blood to the periphery during diastole to maintain blood flow in the body

Question 18

in systemic circulation what is one word that describes pressure on the arterial side?

Answer 18

pulsatile

Question 19

where is the greatest pulse pressure?

Answer 19

left ventricle

Question 20

what happens to pressure with increasing distance from the heart?

Answer 20

it decreases

Question 21

what happens to pulse pressure with age?

Answer 21

increases

Question 22

what happens to stroke volume with age?

Answer 22

goes up

Question 23

why does the dicrotic notch (incisura) occur?

Answer 23

there is a reversal of pressure (ventricle pressure is lower than aortic pressure) causing a momentary reversal of blood flow which closes aortic valves and creases a transient increase in aortic pressure

Question 24

the reversal of flow seen directly before the aortic valve closure is important for what?

Answer 24

perfusion of the coronary arteries

Question 25

what is the equation for tension?

Answer 25

T= transmural pressure x radius

Question 26

define tension

Answer 26

a force exerting its effect along the wall circumference and is often described as “the force that would pull apart a LONGITUDINAL slit in the wall”

Question 27

how do blood vessels respond to pressure changes?

Answer 27

by expanding or contracting their vessel

or by increasing the opposing force by smooth muscle contraction

Question 28

what is a possible consequence of increased tension

Answer 28

aneurism

Question 29

without any sympathetic stimulation, at what pressure will flow completely stop?

Answer 29

~ 6mmHg

Question 30

vasoconstriction in response to hemorrhage can do what?

Answer 30

mobilize blood from the venous reseve

Question 31

a sympathetic response to hemorrhaging would do what to a compliance curve?

Answer 31

shift it to the left so that BP can be maintained at a lower volume

Question 32

what is raynaud’s disorder?

Answer 32

Brief episodes of vasospasm (narrowing of the blood vessel diameter)

Question 33

in raynaud’s disorder what commonly triggers the vasospasms?

Answer 33

cold temperature or emotional stress

Question 34

what is the typical sequence of a reynaud’s attack

Answer 34

digits first turn white (ischemia), blue (deoxygenation) then red (reprofusion). After it subsides, blood flow can return but can be with discomfort