QuestionSBA
QuestionChoice
This is incorrect. The primary pacemaker of the heart is the sinoatrial node. Atrial myocytes can display abnormal pacemaker activity, however, and this is believed to play an important role in the development of atrial fibrillation.
10025989
e
Atrial myocytes
QuestionChoice
This is incorrect. Purkinje fibres are responsible for the conduction of impulses from the right and left bundle branches to the ventricular myocytes. Similarly to the atrioventricular node, they have latent pacemaker cells that are normally overridden in the healthy heart due to the sinoatrial node having the fastest rate.
10025987
c
Purkinje fibres
QuestionChoice
This is incorrect. The bundle of His is responsible for conducting the electrical impulse down the interventricular septum from the atrioventricular node. It is not the primary pacemaker of the heart.
10025988
d
Bundle of His
QuestionChoice
This is correct. The SAN is situated in the upper part of the wall of the right atrium. Cardiac pacemaker cells are mostly found in the SAN. The pacemaker cells continuously generate electrical impulses, thereby setting the normal rhythm and rate in a healthy heart; hence the SAN is known as the primary pacemaker.
10025985
a
Sinoatrial node (SAN)
QuestionChoice
This is incorrect. The AVN is responsible for conducting electrical impulses from the atria to the ventricles via the bundle branches. The AVN has latent pacemaker cells, however, the rate of the sinoatrial node is faster, so these are normally overridden.
10025986
b
Atrioventricular node (AVN)
Concept
Chapter
2693
3962
Cardiac Action Potential Generation and Conduction
Topic
159
Cardiovascular physiology
17595
A 22 year old male is diagnosed with atrial fibrillation (AF) after presenting to his General Practitioner with palpitations. AF is caused by a problem in the pacemaker cells of the heart.

Which of the following regions of the heart is the primary pacemaker?
a