i. At -60mv charge begins to increase
ii. When it is reached to -40mv, stimulates gated ion channels to open and Ca2+ rushes into cardiocytes causing an increase of electrical charge (depolarization)
iii. When the membrane potential reaches >0mv, Pacemaker Potential becomes +, stimulates other channels to open rushing K+ out of cardiocytes (repolarization), charge will reach to -60mv again.
iv. It takes .8sec for 1 AP to occur causing a contraction
v. About the same time that an AP is produced Rt. Atrium will contract.
vi. After 50msec, the SA node will send an electrical signal to the AV node which will delay the AP by .100msec.
vii. The AP will travel to the AV branches, Purkinje Fibers
viii. Ventricles will depolarize after 200msec.
ix. Both ventricles will contract almost simultaneously.