Fast and slow action potentials

Slow response action potentials: i.e SAN 

NOTE: LOOK AT RIGHT PICTURE

Phases of SAN action potential

Phase 4: gradual spontaneous depolarisation = pacemaker potential 

• Decays from -60mV to -40mV due to:
• less potassium ionss flowing out though potassium channels.and a slow inward movement of sodium ions and calcium ions. 

Phase 0: more repid depolarisation due to:

• calcium entry through voltage-operated calcium channels [T-type and…