3.2.4. Venous System Function

Question 1

Function of arterial system

Answer 1

1. Maintain pressure to ensure perfusion of organs

2. Act as a filter to modulate pulsatile blood flow

Question 2

central venous pressure range

Answer 2

2-8 mmHg

Question 3

Venous pressure at the head when standing

Answer 3

-44 mmHg

Question 4

Venous pressure at the feet when standing

Answer 4

88 mmHg

Question 5

venous pulse: a wave pulse

Answer 5

corresponds to atrial contraction

Question 6

venous pulse: c wave pulse

Answer 6

corresponds to tricuspid bulging into atria during systole

Question 7

venous pulse: x decent

Answer 7

corresponds to atrial relaxation

Question 8

venous pulse: v wave pulse

Answer 8

venous pressure rises slowly as atria fills

Question 9

venouse pulse: y descent

Answer 9

corresponds to atria emptying into ventricles while AV valves open during diastole

Question 10

% of blood volume in venous system at normal resting conditions

Answer 10

70%

Question 11

% of blood volume in venous system during exercise

Answer 11

stored blood in venous system reduced from 60% - 70%

Question 12

Vascular function curve: Hemorrhage

Answer 12

Hemorrhage will reduce cardiac output but not change slope of the curve

Question 13

Vascular function curve: Volume infusion

Answer 13

Volume infusion such as saline IV will increase cardiac output but not change slope of the curve

Question 14

Venous system function

Answer 14

1. Blood storage and liberation

2. Regulate return of blood to the heart

Question 15

Mean systemic filling pressure

Answer 15

A point on the vascular function curve in which cardiac output drops to zero L/min. Ultimately, flow will terminate once mean arterial pressure equalizes with central venous pressure at 7 mmHg

Question 16

Vascular function curve: central venous pressure = 0

Answer 16

Here the cardiac output is at it’s maximum. Below this, no venous return to the heart will occur and veins will collapse.

Question 17

Vascular function curve: increasing venous tone

Answer 17

increase cardiac output but not change slope of the curve

Question 18

Vascular function curve: decreasing venous tone

Answer 18

Decrease cardiac output but not change the slope of the curve

Question 19

Vascular function curve: increase total peripheral resistance such as arteriolar constriction

Answer 19

Mean systemic filling pressure does not change. Slope of vascular function curve decreases and cardiac output decreases for a given right atrial pressure

Question 20

Vascular function curve: arteriolar dilation

Answer 20

Mean systemic filling pressure does not change. Slope of the vascular function curve increases and cardiac output increases for a given right atrial pressure

Question 21

Cardiac function curve: Right atrial pressure of zero

Answer 21

Yields cardiac output of zero. There is no preload. As a mental exercise the flask of water or preload is below the heart and the heart will not fill. The cardiac function curve is a representation of the heart with no vessels.

Question 22

Cardiac function curve: maximum cardiac output

Answer 22

Based on the maximum preload to get max cardiac output. The heart can not fill with any further increase in preload pressure.

Question 23

cardiac function curve: increase in contractility, decrease in afterload, or increase in heart rate

Answer 23

cardiac function curve is shifted up and to the left

Question 24

Cardiac function curve: decrease contractility, increase afterload, decrease heart rate

Answer 24

cardiac function curve shifts down and right

Question 25

integrated vascular and cardiac function curve intersection

Answer 25

represents the only conditions where the heart and vessels can functionally coexist

Question 26

integrated vascular and cardiac function curve: heart failure

Answer 26

contractility decreases. cardiac function curve shifts down and right. Cardiac output must remain at a certain value, so the body compensates by increasing blood volume, so the vascular function curve shifts right to restore cardiac output

Question 27

integrated vascular and cardiac function curve: increase in arteriolar constriction (increase in total peripheral resistance).

Answer 27

vascular function curve slope decreases and cardiac output decreases. The body compensates by increasing cardiac contractility to restore cardiac output. The cardiac function curve shifts up and left.

Question 28

integrated vascular and cardiac function curve: exercise

Answer 28

sympathetic stimulation increases contractility, so the cardiac function curve shifts up and left. Sympathetic stimulation decreases peripheral resistance and increases venous tone which increases the slope of the vascular function curve and shifts the curve to the right. This leads to a major increase in cardiac output.