The pacesetter in the heart is called

Options

A. Sino-atrial node (SAN)
B. Atrio-ventricular node (AVN)
C. Purkinje fibres
D. Papillary muscle

Answer

### Step-by-Step Solution:

1. **Understanding the Heart's Electrical System**: The heart has a specialized electrical conduction system that controls the heartbeat. The main components involved are the Sinoatrial node (SAN), Atrioventricular node (AVN), and Purkinje fibers.

2. **Identifying the Pacemaker**: The Sinoatrial node (SAN) is known as the primary pacemaker of the heart. It generates electrical impulses that initiate the heartbeat.

3. **Identifying the Pacesetter**: The Atrioventricular node (AVN) acts as a pacesetter. It receives the electrical impulses from the SAN and conducts them to the ventricles after a slight delay, allowing the atria to contract first.

4. **Understanding the Role of AVN**: The AVN is located in the right atrium and plays a crucial role in coordinating the timing of the heart's contractions. It ensures that the atria contract before the ventricles, which is essential for efficient blood flow.

5. **Conclusion**: Based on the roles of the SAN and AVN, the correct answer to the question "The pacesetter in the heart is called" is the Atrioventricular node (AVN).

### Final Answer:
The pacesetter in the heart is called the Atrioventricular node (AVN).

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