Atrio-ventricular node is present in

Options

A. interventricular septum
B. bundle of His
C. interatrial septum
D. coronary sulcus

Answer

To answer the question about the location of the atrio-ventricular (AV) node, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the AV Node**: The atrio-ventricular node, commonly referred to as the AV node, is a crucial part of the heart's electrical conduction system. It helps coordinate the timing of contractions between the atria and ventricles.

2. **Location of the AV Node**: The AV node is specifically located near the coronary sinus. The coronary sinus is a collection of veins that drains blood from the heart muscle into the right atrium.

3. **Anatomical Position**: The AV node is situated in the interatrial septum, which is the wall that separates the right and left atria of the heart. This is an important detail because it distinguishes the AV node's location from other structures in the heart.

4. **Blood Supply**: In a right dominant heart, the AV node is supplied by the right coronary artery. This is relevant for understanding its vascularization but does not change its location.

5. **Eliminating Incorrect Options**:
- The interventricular septum is the wall separating the right and left ventricles, which is not where the AV node is located.
- The bundle of His is part of the conduction system that carries impulses from the AV node but is not the location of the AV node itself.
- The coronary sinus is a structure surrounding the heart but does not specifically denote the location of the AV node.

6. **Conclusion**: Therefore, the correct answer is that the atrio-ventricular node is present in the interatrial septum.

### Final Answer:
The atrio-ventricular node is present in the interatrial septum.