Phase of cardiac action potential, where calcium channels close & slow potassium channels open :
In cardiac action potential Phase O - Rapid upstroke - due to fast sodium channels- Influx of Na+Phase I - Initial repolarization - fast Na channels - closePhase II - Plateau - due to calcium influx Phase III - Rapid repolarization - Calcium channels close & slow potassium channels open Phase IV - Resting membrane potential - - 90 mv
Phase I
Phase II
Phase III
Phase IV
JIPMER 2019