Electrical activity of the heart

Question 1

Describe the phases of ventricular action potentials

Answer 1

Phase 0 - Depolarisation: sodium channels open and sodium enters. Calcium channels also open.
Phase 1 - Partial repolraisation. Calcium ions enter
Phase 2 - Plataeu: Potassium channels open and there is a slow efflux of potassium ions
Phase 3 - Repolarisation: Fast efflux of potassium ions, increased K+ permeabilit
Phase 4 - Resting membrane potential. Calcium ions decrease