Cardio - Physiology (Part 2) Flashcards Preview

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Flashcards in Cardio - Physiology (Part 2) Deck (117)
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1

What type of murmur occurs in late systole after a midsystolic click and is loudest at S2?

Mitral prolapse

2

In tricuspid stenosis, the murmur gets louder with _____ (inspiration/expiration) due to increased blood flow into the right atrium.

Inspiration

3

Which murmur is often due to age-related calcification?

Aortic stenosis

4

What happens during phase 3 of the cardiac myocyte action potential?

Rapid repolarization due to increased permeability to potassium

5

During phase 4 of the action potential in a ventricular myocyte, to which ion is the membrane highly permeable?

Potassium; as a result, the resting potential of the cell is close to that of potassium

6

What happens during phase 0 of the cardiac myocyte action potential?

Rapid depolarization due to increased sodium permeability

7

What happens during phase 1 of the cardiac myocyte action potential?

Initial repolarization due to increased potassium permeability

8

What happens during phase 2 of the cardiac myocyte action potential?

Electrical plateau due to equivalent calcium influx and potassium efflux

9

What happens during phase 3 of the cardiac myocyte action potential?

Rapid repolarization due to potassium efflux that returns the cell to a more negative potential

10

What is the voltage value of the resting potential of a ventricular myocyte?

- 85 mV; the value is maintained by the sodium/potassium pump and high permeability to potassium

11

How long does the effective refractory period of the cardiac myocyte last?

For the duration of the action potential until the cell returns to resting potential

12

Cardiac myocytes in which locations have pacemaker action potentials?

The sinoatrial and the atrioventricular nodes

13

What happens in phase 0 of the pacemaker action potential?

Voltage-gated calcium channels open

14

The lack of voltage-gated sodium channels in pacemaker cells results in what effect on cardiac conduction?

A slowed conduction velocity through the atrioventricular node to prolong transmission from the atria to the ventricles

15

As compared with the myocardial action potential, which phases are absent from the pacemaker potential?

Phases 1 and 2

16

What happens in phase 4 of the cardiac pacemaker action potential?

Slow diastolic depolarization due to increased permeability to sodium ion

17

During the pacemaker action potential, the slope of which phase determines the heart rate?

Phase 4

18

How does acetylcholine affect the rate of diastolic depolarization and heart rate?

It decreases the rate of diastolic depolarization (the slope of phase 4 of the action potential) and thus decreases heart rate

19

What happens in phase 3 of the cardiac pacemaker action potential?

Inactivation of the calcium channels and activation of the potassium channels

20

Sympathetic stimulation _____ (decreases/increases)the possibility that If channels are open.

Increases; as a result, the pacemaker cell depolarizes more frequently and the heart beats faster

21

Which ion channels in a pacemaker cell are permeable to sodium?

If channels

22

On an electrocardiogram, what does the P wave represent?

Atrial depolarization

23

On an electrocardiogram, what does the PR segment represent? How long is a normal PR interval?

Conduction delay through the atrioventricular node; normally less than 200 msec

24

On an electrocardiogram, what does the QRS complex represent? What is considered a normal QRS duration?

Ventricular depolarization; normally less than 120 msec

25

What segment of the electrocardiogram corresponds with the mechanical contraction of the ventricles?

The QT interval

26

On an electrocardiogram, ventricular repolarization is represented by what?

The T wave

27

In what part of the electrocardiogram is atrial repolarization?

Atrial repolarization is masked within the QRS complex

28

On an electrocardiogram, what does the ST segment represent?

The isoelectric state after the ventricles have been depolarized and before repolarization

29

What do U waves on an electrocardiogram represent?

Hypokalemia or bradycardia

30

What is the physiologic benefit of the atrioventricular delay?

It allows time for ventricular filling