Cardiac Physiology

Question 1

isovolumetric contraction

Answer 1

between mitral valve closing and aortic valve opening

Question 2

isovolumetric relaxation

Answer 2

between aortic valve closing and mitral valve opening

Question 3

retrograde flow

Answer 3

blood flows from aorta into ventricle at the end of reduced ejection

Question 4

First heart sound (S₁)

Answer 4

oscillation of blood and vibration in ventricles, following closure of A-V valves; lower pitched, more intense and longer than the second sound

Question 5

Second heart sound (S₂)

Answer 5

oscillation of blood in aorta and pulmonary artery, following closure of aortic and pulmonic valves

Question 6

Third heart sound (S₃)

Answer 6

early diastole; low in pitch and intensity in the normal heart; increased intensity during heart failure; vibration of blood during ventricular filling

Question 7

Fourth heart sound (S₄)

Answer 7

atrial contraction; low in intensity and pitch; sometimes heard in children bc they have thin chest wall

Question 8

End Diastolic Volume

Answer 8

volume of blood in full ventricle; preload

Question 9

End Systolic Volume

Answer 9

Volume of blood in ventricles at the end of systole

Question 10

Cardiac contractility curve

Answer 10

relates ventricular volume to how much pressure the ventricles can generate; the more you stretch a ventricle, the more force it generates up to a maximum

Question 11

Preload

Answer 11

the pressure (volume?) in the ventricles at the end of diastole

Question 12

Afterload

Answer 12

the aortic pressure against which the ventricle has to pump (to open the aortic valve); the point at which the aortic valve opens

Question 13

Systolic pressure

Answer 13

peak pressure in the AORTA (not the ventricle)

Question 14

Diastolic pressure

Answer 14

minimum pressure in the AORTA (not the ventricle)

Question 15

Peak ventricular systolic pressure

Answer 15

max pressure in the ventricle

Question 16

End Diastolic Pressure

Answer 16

pressure in ventricle just before mitral valve closes

Question 17

Stroke Volume

Answer 17

Difference between the end diastolic volume and the end systolic volume

Question 18

Cardiac Output

Answer 18

Stroke volume x Heart rate

Question 19

What is the effect of increasing afterload?

Answer 19

decreased stroke volume

increased peak systolic pressure

decreased shortening velocity (is this contraction?)

Question 20

What is the effect of decreasing afterload?

Answer 20

increased stroke volume

decreased peak systolic pressure

Question 21

What is the effect of increasing contractility?

Answer 21

increased stroke volume

increased peak systolic pressure

Question 22

How is contractility increased?

Answer 22

increased sympathetic activity (increased Ca²⁺, causing ventricles to contract to a greater extent)

Question 23

Effect of decreasing contractility?

Answer 23

Decreased stroke volume

Decreased peak systolic pressure

Question 24

How is contractility decreased?

Answer 24

1. withdrawing sympathetic activity
2. increasing parasympathetic activity

Question 25

How does your body compensate for an increased afterload?

Answer 25

increase contractility Increase preload (increase EDV)