Terminology

Question 1

Functional refractory period

FRP

Answer 1

The coupling interval which first results in a measurable degree of delay in impulse conduction

Question 2

Effective refractory period

ERP

Answer 2

The longest coupling intervals to be associated with block

Question 3

Resting transmembrane potential

Answer 3

Voltage difference between the inside and outside of the cell fiber

Question 4

Action potential

Answer 4

Cellular characteristics of depolarization and repolarization. The action potential consist of five phases

Question 5

Definition of phase 0 of action potential

Answer 5

The depolarization phase, during this phase the rapid sodium channels are stimulated to open, causing the resting transmembrane potential to spike from -90 mV to 20 mV

Question 6

Definition of phase 1 of the action potential

Answer 6

Early repolarization

Question 7

Definition ofPhase 2Of the action potential

Answer 7

The plateau phase. This phase, mediated by the slow calcium channels, essentially disrupts and delays the repolarization started in phase 1 and prolongs the refractory period

Question 8

Definition of phase 3 of the action potential

Answer 8

The end of repolarization.

Question 9

Which phases of the action potential represent the refractory period of cardiac tissue?

Answer 9

The end of phase 0 through the end of phase 3 represents the refractory period Of cardiac tissue

Question 10

Definition of phase 4 of the action potential

Answer 10

The resting phase. It is during this phase that and some cardiac cells ions lake back-and-forth between membranes and cause a gradual increase in the transmembrane resting potential. When the potential voltage reaches the threshold voltage the cell repolarizes.

Question 11

Define automaticity

Answer 11

Spontaneous depolarization of the cell membrane