The Cardiac Cycle Flashcards Preview

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Flashcards in The Cardiac Cycle Deck (74):
1

What are the stages of the cardiac cycle?

1) Late diastole (both sets of chambers are relaxed and ventricles fill passively)

2) Atrial systole (atrial contraction forces amll amount of additional blood into ventricles)

3) Isovolumic ventricular contraction (first phase of ventricular contraction pushes AV valves closed but does no create enough pressure to open semilunar valves)

4) Ventricular ejection (ventricular pressure exceeds that in the arteries, opening semilunar valves and blood is ejected)

5) Isovolumic ventricular relaxation (ventricles relax and pressure falls, blood flows back into cusps of semilunar valves and snaps them closed)

2

What happens during late diastole?

Both sets of chambers are relaxed and ventricles fill passively

3

What happens during atrial systole?

Atrial contraction forces a small amount of additional blood into ventricles

4

What happens during isovolumic ventricular contraction?

First phase of ventricular contraction pushes AV valves closed but does not create enough pressure to open semilunar valves

5

What happens during ventricular ejection?

Pressure inside ventricles exceeds pressure in the arteries, the semilunar valves open and blood is ejected

6

What happens during isovolumic ventricular relaxation?

As ventricles relax, pressure in ventricles falls, blood flows back into cusps of semilunar valves and snaps them closed

7

What do the muscles of the heart do as they depolarise?

Contract

8

What causes the valves to open and close?

Raising and decreasing the pressure inside chambers

9

How can you describe the pressure inside the atrium?

Low pressure

10

How can you describe the pressure inside the aorta?

High pressure

11

How can you describe the pressure inside the ventricles?

Balance between high and low pressures

12

What happens as soon as the pressure inside the ventricle is greater than the pressure inside the atrium?

Closes the AV valves

13

What causes the pressure inside the ventricles to continue rising once the AV valves have closed?

Muscles continue to contract until the pressure is greater than the aorta

14

What happens once the pressure inside the ventricles is greater than the pressure inside the aorta?

SL valves open

15

Why does blood pressure continue to rise once the SL valves open?

More cross bridges continue to be formed, causing muscle contraction

16

Why do heart muscles in the ventricles stop contracting?

Calcium is pumped back into the sarcoplasmic reticulum or back into the cell so there are fewer cross bridges

17

What happens once the pressure inside the ventricles drops below that of the aorta?

SL valves close

18

When do the AV valves open?

When the pressure inside the ventricles drops below that inside the atrium

19

Why does pressure inside the aorta closely follow pressure inside the ventricles?

There is nothing between the two when the SL valves are open

20

What is systolic pressure?

Maximum pressure in the aorta

21

What is maximum pressure in the aorta called?

Systolic pressure

22

What is diastolic pressure?

Minimum pressure inside the aorta

23

What is minimum pressure inside the aorta called?

Diastolic pressure

24

What is pulse pressure?

Difference between systolic and diastolic pressure

25

What is the difference between systolic and diastolic pressure called?

Pulse pressure

26

What is mean arterial pressure roughly?

Diastolic pressure plus 1/3 the difference between diastolic and systolic pressure

27

What are the 3 blips in the atrium pressure called?

A wave

C wave

V wave

28

What is the A wave of the atrium pressure?

Atrial contraction increases pressure on blood and pushes it into the ventricle

29

What is the C wave of atrium pressure?

Ventricle contraction pushes the mitral valve shut which pushes on the blood in the atrium and causes the increase in pressure

30

What is the V wave of atrium pressure?

While the ventricle is contracting, blood is flowing from the lungs into the atrium to meet the closed mitral valve, causing the pressure to gradually increase

31

What does EDV stand for?

End diastolic volume

32

What is end diastolic volume (EDV)?

Volume of blood in the ventricle at the end of filling it (diastole)

33

What is the volume of blood in the ventricle at the end of filling it (diastole) called?

End diastolic volume (EDV)

34

What does ESV stand for?

End systolic volume

35

What is end systolic volume (ESV)?

Volume of blood in the ventricle at the end of pumping blood out of it (systole)

36

What is the volume of blood in the ventricle at the end of pumping blood out of it (systole) called?

End systolic volume (ESV)

37

What is stroke volume?

Difference between EDV and ESV

38

What is the difference between EDV and ESV called?

Stoke volume

39

How much blood is usually left in the heart after systole?

60ml

40

Why is not all of the blood pumped out of the heart during systole?

Allows the strength of the contraction to be varied

41

What does stroke volume tell you?

How large a person is, larger people have a greater stroke volume

42

What formula described ejection fraction?

Ejection fraction = SV/EDV

43

What does ejection fraction tell you?

How healthy you are, a healthy person should be 2/3 with the number going down as health declines

44

How does ejection fraction change as health declines?

Decreases

45

What is the rapid ejection phase?

First 1/3 of the ejection phase (systole)

46

What is the first 1/3 of the ejection phase (systole) called?

Rapid ejection phase

47

What is the slower ejection phase?

Second 2/3 of ejection phase (systole)

48

What is the second 2/3 of the ejection phase (systole) called?

Slower ejection phase

49

What is the rapid filling phase?

First 1/3 of the filling phase (diastole)

50

What is the first 1/3 of the filling phase (diastole) called?

Rapid filling phase

51

What is the slower filling phase?

Second 2/3 of the filling phase (diastole)

52

What is the second 2/3 of the filling phase (diastole) called?

Slower filling phase

53

Why is it important that most of the blood returns to the heart during the first 1/3 of diastole?

As if the heart rate is increased most of the cycle is cut at the end of the diastole with only a little of systole being lost

54

How does the right side of the heart compare to the left?

Same heart rate

Same volume

Smaller pressures

55

Why are the pressures of the right side of the heart smaller than the left?

A lot easier to push blood through pulmonary circulation than systemic

56

How does the pressure of the right side of the heart compare to the left?

Pressure of the right side is 1/5 the size

57

What is the diagram called that illustrates the pressures inside the heart?

Pressure-volume loop

58

What is A?

End of systole/start of diastole

Mitral valve opens and blood flows into ventricle

Ventricle is very large so no change in pressure

59

What is B?

Ventricle starts contracting so pressure increases

Causes mitral valve to close and pressure to continue to rise

60

What is C?

Pressure inside ventricle is higher than aorta so aortic valve opens

Pressure continues to rise as ventricle continues to contract

Volume starts to drop as blood is pumped into aorta

61

What is D?

Ventricle pressure is lower than aorta so aortic valve closes

Pressure continues to drop as muscles relax

62

Where is the ESV on a pressure-volume loop?

Top left (D)

63

Where is EDV on a pressure-volume loop?

Bottom right (B)

64

What is the stroke volume on a pressure-volume loop?

Difference between the right and the left

65

What does the area inside a pressure-volume loop tell us?

What volume of blood is pressurised by how much

66

What is a phenocardiogram?

A chart of the sounds made by the heart

67

What is a chart of the sounds made by the heart called?

Phenocardiogram

68

What is A?

Mitral and tricuspid valves closing

69

What is B?

Aortic and pulmonary valves closing

70

What is C?

Stenosis of aortic/pulmonary or regurgitation through mital/tricuspid

71

What is A?

Stenosis of mitral/tricuspid or regurgitation through aortic/pulmonary

72

What is the sound between the noises of the two valves closing?

Diastole

73

What can sometimes be heard between the sounds of the two valves closing?

Murmurs

74

What is A?

Septal defect

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