Myocardial action potential quiz:

Question 1

Phase 0 is also called ______.

What channels open & close?

Answer 1

Rapid Upstroke Depolarization;

Na+ channels open

Question 2

Phase 1 is also called ______.

What channels open & close?

Answer 2

Initial Repolarization;

K+ channels open
Na+ channels

Question 3

Phase 2 is also called ______.

What channels open & close?

Answer 3

Plateau;

Ca2+ channels open for influx; Ca2+ from SR released

K+ close for efflux

Question 4

Phase 3 is also called ______.

What channels open & close?

Answer 4

Rapid repolarization;

Slow–Rectifier K+ Channels open for efflux
Ca2+ channels close

Question 5

Phase 4 is also called ______.

What channels open & close?

Answer 5

Resting Potential;
K+ Channels permeable;
Na+, Ca2+ channels clos

Question 6

By what process is calcium released by the myocyte?

Answer 6

Calcium induced Calcium release from SR

Question 7

How are cardiac myocytes coupled to each other?

Answer 7

Via Gap junctions

Question 8

What is responsible for the Plateau phase?

Answer 8

Balanced K+ efflux and Ca2+ influx

Question 9

Does this action potential occur in the SA & AV nodes?

Answer 9

No

Question 10

Through what phases does the refractory period occur?

Answer 10

Phase 0 – 3