Lesson #3

Question 1

_________ ______ generate a fast response action potential.

Answer 1

contractile myocytes.

Question 2

In pacemaker cells, the diastolic potential is established by:

Answer 2

K+ leak channels, allowing K+ to passively leave the cell.

Question 3

Pacemaker potential (Pre-Potential) is due to a reduction in _________ moving out of the cells, and an increase in ___________ moving into the cell.

Answer 3

1. Potassium.
2. Calcium.

Question 4

What channels do the pacemaker cells use to let calcium in during an action potential?

Answer 4

HCN channels.

Question 5

What happens to the action potential when delayed rectifier channels open early?

Answer 5

Action potential duration is decreased.

Question 6

The plateau phase of the fast response is to -

Answer 6

Prevent tetany.

Question 7

Why does the type of action potential change through out the heart?

Answer 7

Differences in # and types of ion channels.

Question 8

________ ________ must always precede a mechanical event:

Answer 8

Electrical event.