Question

Which of the following is called pacemaker?

• A. AV node
• B. Bundle of His
• C. SA node
• D. Purkinje fibres

Answer 1

Answer: (C)

SA node

The heart muscle's electrical impulses cause the heart to beat. This electrical signal starts at the Sinoatrial (SA) node at the top of the upper-right chamber of the heart. Sometimes the SA node is called the "natural pacemaker" of the heart.The SA node sends electrical impulses at some level, but depending on physical requirements, stress, or hormonal variables, heart rate may still alter. It causes the upper chambers of the heart (the atria) to contract when an electrical impulse is released from this natural pacemaker. Then the signal travels to AV node and then to the bundle of HIs resulting in ventricular contraction.

So, the correct answer is 'SA node'