In this diagram of the heart,which of the following choices correctly identifies A and B?
A) A is the AV node; B is the cardiac pacemaker.
B) A is the SA node; B is the septum.
C) A is the AV node; B is the SA node.
D) A is the SA node; B is the AV node.
E) A is the septum; B is the cardiac pacemaker.

Question

In this diagram of the heart,which of the following choices correctly identifies A and B? 
A) A is the AV node; B is the cardiac pacemaker. 
B) A is the SA node; B is the septum. 
C) A is the AV node; B is the SA node. 
D) A is the SA node; B is the AV node. 
E) A is the septum; B is the cardiac pacemaker.

Quizplus · Accepted Answer

A is the SA node (sinoatrial node), which is the natural pacemaker of the heart. B is the AV node (atrioventricular node), which receives the electrical impulses from the SA node and delays them before passing them on to the ventricles. Therefore, choice D correctly identifies both nodes.

In This Diagram of the Heart,which of the Following Choices