Regulation of Cardiac Output and Venous Return

Question 1

What is meant by preload?

Answer 1

volume of blod in ventricles at end of diastole

Question 2

When is preload increased?

Answer 2

• hypervolemia
• regurgitation of cardiac valves
• heart failure

Question 3

What is afterload?

Answer 3

the resistance the left ventricle must overcome to circulate blood

Question 4

When is afterload increased?

Answer 4

• hypertension
• vasocontriction

Question 5

When preload is increased what effect does it have on stroke volume and cardiac output?

Answer 5

increases both

deals with diastolic volume

Question 6

When preload is decreased what effect does it have on stroke volume and cardiac output?

Answer 6

decreases both

deals with systolic volume

Question 7

When afterload is decreased what effect does it have on stroke volume and cardiac output?

Answer 7

increases both

Question 8

When afterload is increased what effect does it have on stroke volume and cardiac output?

Answer 8

both are decreased

Question 9

What is cardiac output?

Answer 9

rate of blood entering the central venous pool of blood

Question 10

What is venous return?

Answer 10

rate of blood entering the central venpus pool of blood

Question 11

Arterial and venous pressures are affected by what?

Answer 11

cardiac output

Question 12

Increases in cardiac output can do what do arterial and venous pressure?

Answer 12

• increase arterial, decrease venous
• caused by redistribution of blood voume

Question 13

In myocardial damage, what does reduced cardiac output result in?

Answer 13

• reduced arterial pressure
• increased venous pressure

Question 14

What is the cardiac function curve determined by?

Answer 14

• determined by cardiac components
• frank-sterling law, contractility

Question 15

How does right arterial pressure affect cardiac output?

Answer 15

central venous pressure (indep. variable) vs cardiac output (depend. variable)

Question 16

What is the vascular function curve determined by?

Answer 16

• determined by vascular components
• resistance, blood volume, compliances

Question 17

How does cardiac output affect right atrium pressure?

Answer 17

central venous pressure (depend. variable) vs cardiac output (independ. variable)

Question 18

If you increase sympathetic stimulation of the heart what type of ionotropic effect does it have in cardiac contractility?

Answer 18

postive

Question 19

If you increase parasympathetic stimulation of the heart what type of ionotropic effect does it have in cardiac contractility?

Answer 19

negative

Question 20

What is the effect of increased blood volume in circulatory blood volume?

Answer 20

higher cardiac output and right atrium pressure

Question 21

What is the effect of decreased blood volume in circulatory blood volume?

Answer 21

lower cardiac output and right atrium pressure

Question 22

An increase in TPR has what effect ?

Answer 22

• increase in afterload
• decrease in cardiac output
• reduce slope of vascular function curve

Question 23

What are the baroreceptor reflex responses to hemorrhage?

Answer 23

• increase sympathetic outflow
• increase in heart rate, contractility, cardiac output, constriction of arterioles
• decrease in constriction of veins

Question 24

What is the renin-angiotensin 2- aldosterone responses to hemorrhage?

Answer 24

• increase in angiotensin 2
• increase in TPR
• increase in aldosterone, Na reabsorption, blood volume

Question 25

What are the capillaries responses to hemorrhage?

Answer 25

• decrease in hydrostatic pressure
• increase in fluid absorption
• increase in blood volume

Question 26

The capillaries, baroreceptor reflex, and renin-angiotensin 2- aldosterone all lead to the result of what?

Answer 26

the arterial pressure returning to normal

Question 27

What is the central command response to exercise?

Answer 27

• increase in sympathetic outflow
• decrease in parasympathetic outflow
• increase in heart rate, contractility, cardiac output
• decrease constriction of veins

Question 28

What is the local response to exercise?

Answer 28

• increase vasodilator metabolites
• decrease TPR

Question 29

Central commands and local responses lead to the result of what?

Answer 29

increase blood flow to skeletal muscle