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Flashcards in Cardiac Cycle Deck (40)
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1

When do heart valves produce a sound?

When they shut NOT when they open

2

Explain an overview of the cardiac cycle?

The orderly depolarization and repolarization sequence triggers a recurring cardiac cycle of atrial and ventricular contractions and relaxations

3

Diastole. what happens?

The hearts ventricles are relaxed and fill with blood

4

Systole. What happens?

The heart ventricles contract and pump blood into the aorta and pulmonary artery

5

Events during the cardiac cycle?

Passive Filling Atrial contraction Isovolumetric ventricular contraction Ventricular ejection Isovolumeteric ventricular relaxation

6

Isovolumetric?

no corresponding volume change- ventricular volume does not change because all valves are closed at this time

7

What is the pressure in the atria and ventricles during the passive filling stage?

Close to 0

8

What occurs in the passive filling stage?

AV valves open so venous return flows into the ventricles

9

What is the aortic pressure during passive filling?

~80mmHg

10

The aortic valve is closed during passive filling. True or False?

True it is closed

11

How full do ventricles become by filling?

80% full

12

What happens in the right side of the heart during passive filling?

Basically the same as the left except the pressures (right ventricular and pulmonary artery) are much lower

13

Explain the valves in passive filling?

Aortic valve is closed Mitral is open Pulmonary is closed Tricuspid is open

14

What does the P wave in an ECG signal?

Atrial depolarization

15

When does the atria contract on an ECG?

Between the P wave and the QRS

16

What does atrial contraction achieve?

The end diastolic volume

17

When does ventricular contraction start?

After the QRS wave on an ECG

18

What happens in Isovolumeteric contraction?

Ventricular pressure rises- when it exceeds atrial pressure the AV valves ShUt Producing the first LUB sound Aortic valve is still shut so no blood can enter or leave ventricles yet - Ventricular pressure rises very steeply- the tension is rising around a closed volume

19

What happens when ventricular pressure exceeds atrial pressure?

The AV valves shut

20

Why is it called isovolumeteric?

The tension is rising around a closed volume

21

Explain the pressures in ventricular ejection?

When the ventricular pressure exceeds aorta/pulmonary artery pressure

22

What happens in ventricular ejection?

Ventricular pressure exceeds pressure in aorta/pulmonary artery. Aortic/pulmonary valve opens (silently) Stroke volume is ejected by each ventricle leaving behind the end systolic volume. Aortic pressure rises

23

What does ventricular ejection leave behind?

End Systolic volume

24

SV and end volumes equation?

SV= EDV- ESV

25

What does the T wave in an ECG represent?

Ventricular repolarization

26

What happens in ventricular repolarization (part of VE)

Ventricles relax and ventricular pressure starts to fall When V pressure falls below aortic/pulmonary pressure- aortic pulmonary valves shut Producing the second heart beat DUB

27

What produces the DUB sound?

When ventricular pressure falls below that of aortic/pulmonary and the aortic and pulmonary valve shut

28

What does valve vibration produce in an aortic pressure curve?

Dicrotic notch

29

What happens in isovolumeteric ventricular relaxation?

Closure of aortic/pulmonary valves signal the start of this time AV valve is shut so therefore ventricle is closed box Tension falls around a closed volume

30

What happens when ventricular pressure falls below atrial pressure?

AV valves open Heart starts a new cycle