Cardiac Cycle

Question 1

When do heart valves produce a sound?

Answer 1

When they shut NOT when they open

Question 2

Explain an overview of the cardiac cycle?

Answer 2

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

Question 3

Diastole. what happens?

Answer 3

The hearts ventricles are relaxed and fill with blood

Question 4

Systole. What happens?

Answer 4

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

Question 5

Events during the cardiac cycle?

Answer 5

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

Question 6

Isovolumetric?

Answer 6

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

Question 7

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

Answer 7

Close to 0

Question 8

What occurs in the passive filling stage?

Answer 8

AV valves open so venous return flows into the ventricles

Question 9

What is the aortic pressure during passive filling?

Answer 9

~80mmHg

Question 10

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

Answer 10

True it is closed

Question 11

How full do ventricles become by filling?

Answer 11

80% full

Question 12

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

Answer 12

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

Question 13

Explain the valves in passive filling?

Answer 13

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

Question 14

What does the P wave in an ECG signal?

Answer 14

Atrial depolarization

Question 15

When does the atria contract on an ECG?

Answer 15

Between the P wave and the QRS

Question 16

What does atrial contraction achieve?

Answer 16

The end diastolic volume

Question 17

When does ventricular contraction start?

Answer 17

After the QRS wave on an ECG

Question 18

What happens in Isovolumeteric contraction?

Answer 18

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

Question 19

What happens when ventricular pressure exceeds atrial pressure?

Answer 19

The AV valves shut

Question 20

Why is it called isovolumeteric?

Answer 20

The tension is rising around a closed volume

Question 21

Explain the pressures in ventricular ejection?

Answer 21

When the ventricular pressure exceeds aorta/pulmonary artery pressure

Question 22

What happens in ventricular ejection?

Answer 22

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

Question 23

What does ventricular ejection leave behind?

Answer 23

End Systolic volume

Question 24

SV and end volumes equation?

Answer 24

SV= EDV- ESV

Question 25

What does the T wave in an ECG represent?

Answer 25

Ventricular repolarization

Question 26

What happens in ventricular repolarization (part of VE)

Answer 26

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

Question 27

What produces the DUB sound?

Answer 27

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

Question 28

What does valve vibration produce in an aortic pressure curve?

Answer 28

Dicrotic notch

Question 29

What happens in isovolumeteric ventricular relaxation?

Answer 29

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

Question 30

What happens when ventricular pressure falls below atrial pressure?

Answer 30

AV valves open Heart starts a new cycle

Question 31

What is the first heart sound called and caused by?

Answer 31

S1 Caused by closure of mitral and bicuspid valves

Question 32

What does S1 indicate?

Answer 32

The start of systole

Question 33

What is the second heart sound called and caused by?

Answer 33

S2 Closure of aortic and pulmonary valves

Question 34

What does S2 indicate?

Answer 34

The end of systole and beginning of diastole

Question 35

How does arterial pressure not reach 0 in diastole?

Answer 35

Pressure from external environment?

Question 36

When does JVP occur?

Answer 36

After right atrial pressure waves

Question 37

What does JVP stand for?

Answer 37

Jugular venous pressure

Question 38

Diagram showing relative heart pressures during cariac cycle?

Answer 38

Question 39

Explain this diagram?

Answer 39

This is a JVP diagram to show it happens after right atrial pressure waves a is atrial contraction c bulging of tricuspid valve into atrium during ventricular contraction v is a rise of atrial pressure during atrial filling