Chapter 1.a Concept Review: Action Potential - Myocardial Cell Flashcards
how many phases is action potential of myocardial cell divided into?
5; phases 0, 1, 2, 3, 4
phase 0 represents
ventricular depolarization
rapid depolarization depends on initial entry of which electrolyte?
Na+
resting potential of myocardial cell
-90 mV
positive potential of myocardial cell
20 mV
what is phase 0, ventricular depolarization, represented as on the ECG?
QRS wave
ventricular repolarization occurs during which phases?
phases 1, 2, and 3
which electrolyte channel is closed (and inactivated), and which electrolyte channel is opened during phase 1?
- Na+
- K+
during phase 2, neutral potential is maintained by balancing which electrolytes?
- efflux of K+
- ENTRY of Ca++
phase 2 is AKA
plateau phase
what is phase 1 represented as on the ECG?
J point
what is phase 2 represented as on the ECG?
ST segment
what does phase 3 represent?
rapid repolarization to negative resting potential
which electrolytes are opened and closed during phase 3, rapid repolarization?
- continued efflux of K+
- CLOSURE of Ca++
what is phase 3 represented as on the ECG?
T wave