What is the role of the pacemaker (SAN)?

A. It controls the release of epinephrine (adrenaline).
B. It sends nerve impulses to the ventricles.
C. It regulates the activity of the medulla.
D. It changes the frequency of muscle contraction in the heart.

D

There was a complaint on G2s about the use of the SAN in the question instead of the full name of the sinoatrial node. The guide uses the acronym, so it is fair to use it in the exam. This question showed a bad discrimination factor. Many candidates chose answer B instead of D.