PSL301: Cardio 3 Flashcards Preview

PSL301 > PSL301: Cardio 3 > Flashcards

Flashcards in PSL301: Cardio 3 Deck (66):
1

Heart is stimulated by the...

sympathetic cardioacceletatory center

2

Heart is inhibited by the...

parasympathetic cardioinhibitory center

3

Where is the sympathetic cardioacceletatory center located?

Medulla oblongata

4

Where is the parasympathetic cardioinhibitory center located?

Medulla oblongata

5

How does the parasympathetic cardioinhibitory center connect to the heart?

Interneuron to dorsal motor nucleus of vagus -> Vagus nerve -> heart

6

How does the sympathetic cardioacceletatory center connect to the heart?

Interneuron to tharacic spinal cord (sympathetic trunk) -> PS fibres to sympathetic trunk ganglion -> interneurons to heart

7

Which neuron activates the PSm pathway?

ACh binding to muscarinic receptors on autorhythmic cells

8

Which neuron activates the Sm pathway?

NE binding to B1-receptors on autorhythmic cells

9

Autonomic NTs alter...

heart rate

10

Catecholamines modulate...

cardiac contraction

11

Phospholamban

Integral membrane protein that regulates the Ca2+ pump in cardiac muscle and skeletal muscle cells

12

The cAMP system activated by NE/E {P}...

1. Voltage gated Ca channels
2. Phospholamban

13

What does the {P} of phospholamban result in?

Stimulate Ca-ATPase on SR

14

What does the {P} of voltage gated Ca channels result in?

More Ca from ECF can come into the cell

15

How do catecholamines affect cardiac contraction?

1. Increase Ca stores in SR
-> more Ca released
-> more forceful contraction

2. Faster removal of Ca from cytosl
-> shorter duration of contraction

16

Increase of Ca from ECF will result in...

1. More Ca in SR
2. More Ca released when it's time to contract

17

What does ECG measure?

Summed electrical activity of all cells
Recorded from surface of body

18

The ____ Triangle places electrodes on the right arm, left arm, left leg.

Einthoven's

19

What is the purpose of Einthoven's Triangle?

Places the heart in the middle

20

Einthoven's law

Lead II - Lead I = Lead III

21

What does a lead consist of?

2 electrodes: 1 + and 1 -

22

The waves of the ECG

P QRS T

23

How many beats can be seen in 1 second?

Almost 2 full waves / beats

24

P wave = activity at...

Atria

25

QRS = activity at...

ventricle

26

T = ...

ventricle diastole signal

27

When does atria systole happen on the ECG?

Somewhere during the QRS

28

What intervals is the ECG divided into?

PR interval (beginning of P -> beginning of Q)

QT interval (beginning of Q -> end of T)

29

PR segment

End of P -> beginning of Q

30

QRS complex

Beginning of Q -> end of S

31

ST segment

End of S -> beginning of T

32

Major difference between ECG & myocardial contractile cell AP

Since myocardial contractile cell AP is measured from a single cell, the voltage change is much greater than the ECG (110 mV vs. 1 mV)

33

Mechanical pumping events of the cardiac cycle

1. Late diastole
2. Atrial systole
3. Isovolumic ventricular contraction
4. Ventricular ejection
5. Isovolumic ventricular relaxation

34

What lasts longer, systole / diastole?

Diastole

35

What is the standard diagram used to combine ECG, pressure, heart sounds, and left ventricular volume?

Wiggers diagram

36

What does Wiggers' diagram comprise of?

- ECG graph
- Pressure (atria, ventricles, aorta)
- Heart sounds
- Left ventricular volume

37

ventricular diastole occurs at where on the ECG graph?

after T wave

38

Atrial systole occurs at where on the ECG graph?

Middle of P -> Q

39

Ventricular systole occurs where on the ECG graph?

Q -> end of T

40

When is volume highest in left ventricle? What is this called?

After arterial systole
End Diastole Volume (EDV)

41

When is volume lowest in left ventricle? What is this called?

After ventricular systole
End Systole Volume (ESV)

42

Max volume of ventricle

135 mL

43

On average, how much blood does ventricle pump per beat?

70 mL

44

Pressure changes in the atria are mostly due to...

Activity in the ventricle

45

What is the increase in pressure during ventricular systole?

110 mmHg

46

Dicrotic notch

Slight increase in pressure in the aorta when aortic valves close

47

What causes atrial pressure to drop?

Opening of AV valves

48

Questions to ask when analysing ECG

1. HR normal (60-100 bpm)?
2. Regular rhythm?
3. All waves normal and present (PQRST)?
4. P followed by QRS?
5. PR segment at constant length?

49

What does the ECG look like for 3rd degree block?

- normal P
- S dips lower than usual
- P doesn't always trigger QRS

50

What does the ECG look like for atrial fibrillation?

- no P
- irregular QRS

51

What does the ECG look like for ventricular fibrillation look like?

- no P
- no QRS

52

What does the ECG look like for 2nd degree heart block look like?

- normal P
- normal QRS
- P doesn't always trigger QRS

53

Where does the problem lie when someone has 2nd degree heart block?

AV node (not every signal goes through)

54

Heart block

Impulse generated in SA node does not generate response in ventricles
Ventricles follow a slower pacemaker

55

When is defibrillation used?

ventricular fibrillation

56

Purpose of defibrillator?

Reset all electrical activity in the heart so SA node can take the lead properly

57

How to treat heart block?

Artificial pacemaker

58

Components of ECG

1. Waves
2. Segments
3. Intervals

59

Information from ECG

1. HR
2. Heart rhythm
3. Conduction velocity
4. Condition of myocardium

60

Heart rate too fast

Tachycardia

61

Heart rate too slow

Bradycardia

62

Tachycardia

heart rate too fast

63

Bradycardia

heart rate too slow

64

What acts as the pacemaker for the ventricles during 3rd degree heart block?

Purkinje fibres

65

What is unusual QRS activity typically caused by?

When repairing damage to the heart, it is hard to get it back to normal. Bad repair job.

66

What is atrial fibrillation usually caused by?

- problems with SA node
- problems with atria
- AV node