Cardiac Review

Question 1

What is the Nernst equation?

Answer 1

E(ion)= (61.5mV / z) x log( [ion]out / [ion]in )

Question 2

Flow of which ion is represented by phase 0 of cardiac action potential?

Answer 2

Na+

Question 3

What is represented by phase 1 of cardiac action potential?

Answer 3

abrupt closure of Na+ channels

Question 4

Flow of which ion is represented by phase 2 of cardiac action potential?

Answer 4

Ca++

Question 5

Flow of which ion is represented by phase 3 of cardiac action potential?

Answer 5

K+

Question 6

What channel is responsible for the refractory period of cardiac action potential?

Answer 6

delayed K+ rectifier chanel

Question 7

Flow of which ion is represented by phase 4 of cardiac PACEMAKER action potential?

Answer 7

Na+ (funny channel)

Question 8

Flow of which ion is represented by phase 0 of cardiac PACEMAKER action potential?

Answer 8

Ca++

Question 9

Flow of which ion is represented by phase 3 of cardiac PACEMAKER action potential?

Answer 9

K+

Question 10

Sympathetic stimulation acts on which 2 channels to decrease AP duration?

Answer 10

• shortens phase 4 - ‘funny channel’ (Na+)

- stimulates inward rectifying channel [faster K+ channel of phase 3]

Question 11

parasympathetic stimulation acts on what channel to increase AP duration?

Answer 11

delayed rectifier channel [slow K+ channel of phase 3]