Cardiac Action Potentials Flashcards

1
Q

Pacemaker Cells

A

(Slow APs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Pacemaker Potential

A

Unstable phase 4, Spontaneous Depolarization; Inward current caused by Na+ influx (IF), Inward Ca2+ current (ICa), Decreasing outward K+ current (IK)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

AP upstroke

A

Caused by L-VGCC Ca2+ influx, This SLOW AP triggers the FAST AP seen in the heart (This interaction what allows coordinated heart beat!)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Repolarization

A

Increased K+ efflux (IK), Decreased Ca2+ Influx (ICa)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Contractile Cells

A

(Fast APs); order of phases: 4, 0, 1, 2, 3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Phase 4

A

Resting/resetting the RMP; Na+/K+ pump; RMP is -90mV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Phase 0

A

Depolarization; Influx of Na+ through FAST Na+ channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Phase 1:

A

Early Rapid Repolarization;

FAST Na+ channels close, K+ efflux

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Phase 2

A

Slow Repolarization (plateau phase); Purpose of plateau is to extend AP in cardiac muscle cell is as long as the time the heart is contracting to prevent tetanus, K+ efflux, influx of Ca2+ & Na+ (SLOW Na+ channels)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Phase 3

A

Final Rapid Repolarization; K+ efflux, Ca2+ & SLOW Na+ channels close

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Normal Pacemakers

A

SA node; normally suppresses other “ectopic” foci

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Electrical Conduction System Step 1

A

Action potentials originate in the SA node (pacemaker), and travel across the wall of the atrium to the AV node

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Electrical Conduction System Step 2

A

Action potentials pass through the AV node and along the atrioventricular bundle, which extends from the AV node through the fibrous skeleton into the interventricular septum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Electrical Conduction System Step 3

A

The AV bundle divides into right and left bundle branches and action potentials descend to the apex of each ventricle along the bundle branches

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Electrical Conduction System Step 4

A

Action potentials are carried by the Purkinje fibers from the bundle branches to the ventricular walls

How well did you know this?
1
Not at all
2
3
4
5
Perfectly