The cardiac impules that results into the heart beat is delayed at `:-`

Options

A. Internodal tract
B. AV Node
C. Bundle of His
D. Purkinje fibres

Answer

To answer the question "The cardiac impulses that result in the heartbeat is delayed at:", we need to understand the conduction system of the heart and the role of different components in this system.

### Step-by-Step Solution:

1. **Identify the Components of the Cardiac Conduction System**:
- The heart has a specialized conduction system that includes the SA node (sinoatrial node), AV node (atrioventricular node), bundle of His, and Purkinje fibers.

2. **Understand the Role of the SA Node**:
- The SA node is known as the pacemaker of the heart. It generates electrical impulses that initiate the heartbeat. The impulses from the SA node spread through the atria, causing them to contract.

3. **Recognize the Function of the AV Node**:
- The AV node is located at the junction of the atria and ventricles. Its primary function is to delay the conduction of impulses from the atria to the ventricles. This delay is crucial as it allows the atria to fully contract and fill the ventricles with blood before the ventricles contract.

4. **Evaluate Other Components**:
- The bundle of His and Purkinje fibers conduct impulses after they have passed through the AV node. They do not delay the impulses; rather, they help in the rapid conduction of impulses throughout the ventricles.

5. **Conclusion**:
- The cardiac impulse is delayed at the AV node, allowing for proper filling of the ventricles before they contract.

### Final Answer:
The cardiac impulses that result in the heartbeat are delayed at the **AV node**.