Pressure and Flow in Arteries and Veins

Question 1

when measuring arterial pressure what is the measurement at the start of the tapping?

Answer 1

this is systolic pressure

Question 2

when there is a continuous muffled sound what does this indicate?

Answer 2

the diastolic pressure

Question 3

why are elastic arteries described as pressure reservoirs?

Answer 3

they damp down the pressure variations caused by the beating of the heart

Question 4

what is the pressure wave affected by?

Answer 4

> stroke volume
velocity of ejection
elasticity of arteries
total peripheral resistance

Question 5

what is the normal arterial pressure?

Answer 5

120/80 mmHg

Question 6

why is there a large fall in pressure between arteries and arterioles?

Answer 6

arterioles are resistance vessels, pressure builds up before them.

Question 7

what is the systemic filling pressure?

Answer 7

this is the mall pressure difference that pushes blood back through the veins 20 to 5 mmHg

Question 8

why do external influences effect flow in veins?

Answer 8

because they are distensible and collapsible

Question 9

what is the effect of standing up on the vcs of the legs?

Answer 9

> decrease in end diastolic volume
> decrease in preload
> decrease in stroke volume
> decrease in cardiac output
> MAP
> can cause orthostatic hypotension

Question 10

what can cause venous collapse in the neck?

Answer 10

standing up

Question 11

what happens to the heart when you stand up?

Answer 11

it decreases in size

Question 12

when you stand how much pressure is added to your legs by the venous system?

Answer 12

80mmHg

Question 13

when you stand how much pressure is removed from your head by the venous system?

Answer 13

40mmHg

Question 14

why might a guardsman standing for long periods of time faint?

Answer 14

because of the sustained contraction of his leg muscles the veins in his leg are collapsed and blood cannot return to the heart.

Question 15

what effect will rhythmic exercise have of the diastolic volume?

Answer 15

the periodic contraction and relaxation increases diastolic volume

Question 16

describe the effects of the respiratory pump

Answer 16

breathing creates a negative pressure in the thorax and a positive pressure in the abdomen. these pressures are transmitted to the vessels increasing the gradients. breathing harder and faster therefor increases preload

Question 17

what is the systemic filling pressure>

Answer 17

this is the pressure created by the ventricles and transmitted through the vascular tree to the veins