Summary
Ventricular action potentials are electrical impulses generated by the ventricular cells of the heart, crucial for initiating and coordinating the contraction of the ventricles. These action potentials have five distinct phases (0 to 4), each characterized by specific ion movements across the cell membrane.
Channels:
- Na+ fast channels. Active briefly during the phase 0.
- Slow and fast Ca++ channels. Active during the phase 2.
- Leaky K+ channels. Always active.
- Inward rectifying transient K+ channels. Active during the phase 1.
- Inward rectifying delayed K+ channels. Active during the phase 2 early part and phase 3.
- Inward rectifying K+ channels. Active during the phase 3. Primary channels to help restore resting potential.
- Na+/K+ ATPase pump. Restores the ionic imbalance after an action potential has occurred. Moves K+ in and Na+ out of the cells.