What is a role of the pacemaker or sinoatrial node (SAN)?
A. To initiate contraction of the ventricle
B. To pass the excitation through Purkinje fibres
C. To originate excitation in myogenic muscle
D. To cause the relaxation of the atria
C. To originate the excitation in the myogenic muscle. The SA node initiates the electrical impulse that goes through the heart and causes the depolarization of the right atrea
