Basics

Question	Answer
Pacemaker action potential phases	4 0 3
Pacemaker action potential phase 4	Slow leak of Na into cell Increases membrane potential from -60mV to -40mV
Pacemaker action potential phase 0	Voltage-gated Ca2+ channels open Mass influx of Ca2+ Depolarisation to 10mV
Pacemaker action potential phase 3	Voltage-gated K+ channels open K+ leaves cell Repolarisation to -60mV
Cardiac myocyte action potential phases	4 0 1 2 3
Cardiac myocyte action potential Phase 4	K+ constantly leaving cell to keep membrane potential at -90mV Na2+ and Ca2+ from neighbouring cell flow into cell via gap junctions, bring membrane potential to -70mV
Cardiac myocyte action potential Phase 0	Voltage-gated Na2+ channels open Membrane potential shoots to 20mV
Cardiac myocyte action potential Phase 1	Voltage-gates Na2+ channels close Voltage-gated K+ channels open Repolarises to 5mV
Cardiac myocyte action potential Phase 2	Ca2+ voltage-gates channels open while K+ is leaving the cell Membrane potential remains the same
Cardiac myocyte action potential Phase 3	Ca2+ channels suddenly close K continues to exit cell Repolarises to -90mV

Resource summary

	Created by Amelia Tuffley about 6 years ago