Question

Which of the following is considered to be the primary pacemaker of the heart?

(a) sino-atrial node

(b) atrio-ventricular node

(c) purkinje fibres

(d) bundle of his

This question was posed to me in an interview for internship.

Question is from Electrodes for ECG topic in portion Bioelectric Signal and Electrodes of Biomedical Instrumentation

Answer 1

Right choice is (a) sino-atrial node

To elaborate: Located in the top right atrium near the entry of the vena cava, are a group of cells known as the sino-atrial node (SA node) that initiates the heart activity. Because this is also considered as the primary pacemaker of the heart. The SA node is 25 to 30 mm in length and 2 to 5 mm in thickness.