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Cardiovascular > Cardiac Cycle > Flashcards

Flashcards in Cardiac Cycle Deck (23):
1

Describe diastole

The relaxation and filling of the ventricles

2

What is the approximate stroke volume?

80ml

3

What is the approximate duration of a single cardiac contraction?

280ms

4

How is cardiac muscle arranged on a gross level?

In a figure of 8 so that it contracts from the base upwards.

5

What prevents inversion of atrioventricular valves?

The cusps attach to papillary muscles via chordae tendinae

6

Approximately how long is the signal delayed at AVN for?

120ms

7

What are the 7 phases of the cardiac cycle?

1: Atrial contraction
2: Isovolumetric contraction
3. Rapid ejection
4. Reduced ejection
5. Isovolumetric relaxation
6. Rapid filling
7. Reduced filling

8

Which phases of the cardiac cycle occur is systole?

2, 3 and 4

9

Approximately how long does the full cardiac cycle take?

0.9 secs

10

Approximately how much time is spent in systole and how much in diastole?

1/3 systole
2/3 diastole

11

What do we plot in a Wiggers diagram?

Aortic pressure
Atrial pressure
Ventricular pressure
Ventricular volume
ECG
Phonocardiogram

12

What is the A wave in atrial pressure?

The rise in atrial pressure due to atrial systole.

13

What is the approximate end diastolic volume?

120ml

14

What causes the C wave in atrial pressure?

Closing of the mitral valve

15

In which phase does S1 occur?

Phase 2: the atrioventricular valves close to begin systole

16

What causes the X descent in atrial pressure?

The atrial pressure initially decreasing as the atrial base is pulled as the ventricle contracts.

17

What causes the V wave in atrial pressure?

Gradual rise of pressure due to continued venous return from the lungs.

18

What is the approximate end systolic volume?

40ml

19

How do we work out stroke volume?

EDV - ESV

20

In which phase is the second heart sound?

Phase 5: outflow valves close as systole is finished

21

What causes the Y descent in atrial pressure?

Fall in atrial pressure due to the opening of the atrioventricular valves.

22

What can cause a normal 3rd heart sound?

We can hear ventricular filling

23

Describe systole

The contraction and ejection of blood from ventricles