Sino-atrial node (SAN) - An area of the heart muscle in the right atrium that initiates a wave of electrical excitation across the atria.
Atrio-ventricular node (AVN) - The only conducting area of tissue in the wall of the heart between the atria and ventrcles through which electrical excitation passes from the atria to conducting tissue in the walls of the ventricles.
Cardiac muscle contractions are myogenic.
1) The sino-atrial node acts as a pacemaker, it causes a wave of electrical stimulation to arise and spread over to both atria. It is transferred to the left atrium through the Bachmann's bundle.This causes the atria to contract pushing blood into the…