Physiology Lecture 1 -- The Heart as a Pump Flashcards Preview

Block C - Circulation > Physiology Lecture 1 -- The Heart as a Pump > Flashcards

Flashcards in Physiology Lecture 1 -- The Heart as a Pump Deck (72):
1

When does first heart sound (S1) occur?

Mitral valve closes

2

When does S2 occur?

Aortic valve closes

3

When can S3 occur in terms of Wigger's diagram?

After early rapid/brisk filling via the LA-LV P gradient

4

What is the most common reason for S3 being abnormal?

Congestive heart failure causing increased ventricular pressure (a poor prognostic factor)

5

Define systole in terms of heart events

Mitral valve closes --> aortic valve closes

6

Define diastole in terms of heart events

Aortic valve closes --> mitral valve closes

7

Explain the purpose of isovolumetric contraction

Both valves are closed, so no blood flow occurs as pressure builds in the ventricle to overcome the pressure of the aorta = establish P gradient

8

Pressure gradient during ejection

Left ventricle > Aorta

9

Explain the purpose of isovolumetric relaxation

Both valves are closed, so no blood flow as the left ventricle is given time to relax until its pressure is lower than the atrium

10

Pressure gradient during diastole (post isovolumetric relaxation)

Left atrium > Left ventricle

11

What physical event causes the mitral valve to close?

When P left atrium was higher than P left ventricle and then their P become equal

12

What physical event causes the aortic valve to close?

When P left ventricle was higher than P aorta and then their P become equal

13

What physical event causes the aortic valve to open?

When P aorta was higher than P ventricle and then their P become equal

14

What physical event causes the mitral valve to open?

When P ventricle was higher than P atrium and then their P become equal

15

When can a fourth heart sound be heard?

During the atrial kick

16

How much of the blood is passively emptied from the left atrium to the left ventricle during diastole?

70%

17

What is the purpose of the atrial kick?

Contraction of the atrium to force the remaining 30% of the blood to enter the left ventricle

18

What wave in the wigger's diagram indicates the atrial kick?

a wave

19

What event does the x descent of the Wigger's diagram represent?

Atrial relaxation (early systole)

20

What event does the v wave of the Wigger's diagram represent?

Atrial filling

21

What event does the y descent of the Wigger's diagram represent?

Atrial emptying (early diastole)

22

What might cause an opening heart sound?

Bicuspid aortic valve (an ejection sound)

23

Define this event

Aortic valve closes

24

Define this event

Aortic valve opens

25

Define this event and associated wave

A Wave = Atrial Kick

26

Define this time interval

Atrial systole

27

Define this time interval

Diastalsis

28

Define this interval

Diastole

29

Define this interval

Ejection

30

Define this interval

Isovolumetric contraction

31

Define this interval

Isovolumetric relaxation

32

Define this event

Mitral valve close

33

Define this event

Mitral valve open

34

Define this interval

Rapid inflow

35

Define this interval

Systole

36

Define this wave

v wave = atrial filling

37

Define this wave

x descent = atrial relaxation

38

Define this wave

y descent = atrial emptying

39

Define ESV

Ventricular volume at the end of systole (when aortic valve closes

40

Define EDV

Ventricular volume at the end of diastole (mitral valve closes)

41

Defien inotropy

Contractility, reflected by the relationship between ESV and afterload

42

Define preload

The ventricular volume of blood prior to systole (same as EDV)

43

Define afterload

The pressure (of aorta) that the left ventricle must overcome during systole to eject blood

44

Describe the significance of the relatively shallow slope of the ventricular fillling line of the PV loop

Low slope = low P for changes in V = good compliance

45

Define diastology

PV relationship during diastole (V filling property; compliance)

46

An example of a heart with decreased compliance

Hypertension (thickened ventricular wall)

47

An example of a heart with increased compliance

Cardiomyopathy

48

What happens if left ventricular pressure cannot overcome aortic P

No ejection = keep contracting isovolumetrically

49

Define SV

Stroke Volume = EDV - ESV

Amount of blood ejected to the aorta

50

Define ejection fraction

EF = SV/EDV

Proportion of blood ejected to aorta that was in the ventricle

51

3 factors that affect ventricular performance

Contractility

Afterload

Preload

52

Effect of increased preload on isovolumetric pressure

Increase

53

Define systology

End systolic pressure volume relationship (contracility)

54

Effect of inotropy with constant afterload and preload

Positive inotropic agent = increase contractility = increase SV (blue)

Negative inotropic agent = decrease contractility = decrease SV (red)

55

Predict effect of preload based on Starling's Laws

If V is increased, a NORMAL heart will has more vigorous contractions and produce higher pressures

56

Define premature ventricular contraction

Compensatory pause, which signifies filling of the ventricle = bigger ventricle = very forceful contraction

57

Effect of preload with constant inotropy and afterload

Increased preload = increased SV

58

Normal ejection fraction

60%

59

Effect of afterload (aortic P) with constant preload and inotropy

Increased afterload = decreased SV = lowered EF (since higher ESV)

60

How to treat patients with too much afterload

Decrease afterload with vasodilator (ACE inhibitor), which "unloads" the heart

61

Effect of heart failure on PV loops

Decrease contraciltiy and increased EPV --> decreased SV

62

Afterload

63

Define this event

Aortic valve opens

64

What does this space represent?

Diastole

65

What does this corner represent?

Mitral valve closes

EDV = preload

66

What does this corner represent?

ESV

Aortic valve close

67

What does this slope represent?

Inotropy

68

What does this edge represent?

Isovolumetric contraction

69

What does this edge represent?

Isovolumetric relaxation

70

What does this space represent?

Systole

71

What does this corner represent?

Mitral valve opens

72

What does this width represent?

SV