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Flashcards in 12.1 A Deck (30):
1

What controls the opening of heart valves?

they open passively in response to pressure gradients between different chambers of the heart

2

Describe the resistance of heart valves and the pressure differential needed to open them?

they provide very little resistance, thus very small pressure differentials are sufficient to open them

3

Ventricular systole begins with what event?

mitral valve closure

4

Ventricular systole ends with what event?

aortic valve closure

5

What are EDV and ESV?

end diastolic volume and end systolic volume describe the blood volume in the ventricle at two specific time points

6

EDV - ESV equals what?

stroke volume

7

How does stroke volume relate to EDV?

SV = EDV - ESV

8

The ventricular pressure at the time of aortic valve opening is roughly what?

80 mm Hg

9

The ventricular pressure at the time of aortic valve closure is roughly what?

115 mm Hg

10

What is the equation for ejection fraction?

stroke volume/EDV

11

What is the normal range for ejection fraction?

0.5 to 0.7

12

Ejection fraction is an index of what?

contractility of the heart

13

While diastolic dysfunction is due to impaired filling, systolic dysfunction is due to impaired what?

impaired force generation

14

What happens to the ejection fraction in an individual experiencing diastolic dysfunction?

there is no change, ejection fraction only decreases in systolic dysfunction

15

Describe the rate of ventricular filling during diastole?

it fills rapidly and then the rate begins to slow

16

Most of ventricular filling is due to what?

the pressure gradient more so than atrial contracture

17

Atrial contraction becomes more important to ventricular filling as what occurs?

as heart rate increases and the time for passive filling decreases such as occurs during exercise

18

What is isovolumic ventricular contraction?

the time during which the ventricle is contracting but all the valves are closed, so the volume goes unchanged and the pressure builds

19

Ventricular ejection begins when what occurs?

the ventricular pressure rises above aortic pressure, opening the aortic valve

20

Why does the rate of ventricular ejection decline over the course of each ejection?

- volume decrease during ejection means the pressure decreases
- repolarization begins so contractile force decreases

21

What happens to aortic pressure during ventricular contraction?

it increases and then slightly decreases following ventricular pressure until the aortic valve closes at which point it remains higher than ventricular pressure due to the elasticity of the aorta

22

Ventricular relaxation is said to be _____.

isovolumic

23

What are the two phases of diastole?

isovolumic relaxation and ventricular filling

24

What are the two phases of systole?

isovolumic contraction and ventricular ejection

25

Although the two sides of the heart are in series, the SV does not have to be equal during each beat, what must be equal is...

the average SV over time

26

How does the peak systolic pressure in the right ventricle compare to that of the left ventricle?

it is roughly 1/5 the pressure of the left

27

Why does the mitral valve close slightly before the tricuspid valve?

because the left ventricle has a thicker wall, pressure rises faster in the left ventricle than in the right

28

Which opens slightly earlier, the pulmonic or aortic valve?

the pulmonic valve opens slightly before the aortic during systole because the aortic pressure is greater than that of the pulmonic system

29

Which closes earlier during diastole, the pulmonic or aortic valve?

the pulmonic valve

30

What happens to arterial pressure during ejection?

it increases