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Which is responsible for initiating and ...

Which is responsible for initiating and maintining the rhythmic contractile activity of the heart ?

A

Sino-atrial node (SAN)

B

Atrio-ventricular node (AVN)

C

Purkinje fibres

D

Bundle of his

Text Solution

AI Generated Solution

The correct Answer is:
**Step-by-Step Solution:** 1. **Understanding the Heart's Function**: The heart is responsible for pumping blood throughout the body, and it does so through rhythmic contractions. This rhythmic activity is crucial for maintaining blood circulation. 2. **Identifying the Pacemaker**: The heart has a specialized structure known as the sinoatrial (SA) node, which is often referred to as the pacemaker of the heart. This node is responsible for initiating and regulating the heart's rhythmic contractions. 3. **Location of the SA Node**: The SA node is located in the right atrium of the heart, specifically in the upper right corner. Its position is significant as it plays a key role in starting the electrical impulses that trigger heartbeats. 4. **Function of the SA Node**: The SA node generates electrical impulses that spread through the heart muscle, causing it to contract and pump blood. This process is what maintains the heart's rhythm. 5. **Comparison with Other Structures**: While other structures like the atrioventricular (AV) node, Purkinje fibers, and the bundle of His also play important roles in the heart's conduction system, they do not initiate the heartbeat. The AV node acts as a gatekeeper, the Purkinje fibers help synchronize contractions, and the bundle of His carries impulses through the heart. 6. **Conclusion**: Based on the information above, the structure responsible for initiating and maintaining the rhythmic contractile activity of the heart is the sinoatrial (SA) node. **Final Answer**: The sinoatrial (SA) node is responsible for initiating and maintaining the rhythmic contractile activity of the heart. ---
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