excitable heart Flashcards
1
Q
SA node
A
- unstable phase 4
- automaticity
2
Q
transmembrane conductance
A
- POTASSIUM
3
Q
UNGATED POTASSIUM CHANNEL
A
- constant
- concentration dependent
- it is happening all the time
4
Q
VOLTAGE GATED SODIUM CHANNELS
A
- not constant
- based on electrical charges
- affected by action potential
5
Q
VOLTAGE GATED CALCIUM CHANNELS
A
- not constant
6
Q
VOLTAGE GATED POTASSIUM CHANNELS
A
- not constant
7
Q
Na+ permeability
A
- fast channel
8
Q
Ca2+ permeability
A
- slow channel
9
Q
K+ permeability
A
- slow channel
10
Q
membrane potential (Inside the cell)
A
- 90mV due to potassium going out NORMALLY
- it becomes positive when sodium goes IN
11
Q
Calcium2+ L type channels
A
- stays plateau positive
- going IN
12
Q
Phase 0
A
- fast channels open gNa
- depolarization
- opens and close quickly
13
Q
Phase 1
A
- slight repolarization
- due to transient Potassium current
- closing of the sodium channels
14
Q
arrhythmia
A
treatment to lower mortality beta blockers not anti arrhythmic drugs because it is also a pro drug
15
Q
Phase 2
A
- L-type Ca2+ are open
- Calcium influx (maintains the interior +)
- K channels are closed and leaving efflux
- CALCIUM channel antagonist shorten the plateau (NIFEDIPINE, NICARDIPINE, AMLODIPINE ETC) stops the calcium going IN
- POTASSIUM channel antagonist lengthen the plateau (
