To which of the following, bundles of His passes stimulus for contraction ?

Options

A. Atrium
B. AV node
C. SA node
D. Purkinje fibres

Answer

To solve the question "To which of the following does the bundle of His pass the stimulus for contraction?", we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Role of the Bundle of His**:
- The Bundle of His is a collection of heart muscle cells specialized for electrical conduction. It transmits impulses from the atrioventricular (AV) node to the ventricles.

2. **Identify the Sequence of Electrical Conduction**:
- The electrical conduction system of the heart starts at the Sinoatrial (SA) node, which generates the electrical impulse.
- The impulse then travels to the AV node, where it is briefly delayed to allow the atria to contract and fill the ventricles with blood.

3. **Pathway of the Electrical Signal**:
- After the AV node, the electrical signal travels down the Bundle of His.
- The Bundle of His then branches into the right and left bundle branches, which further lead to the Purkinje fibers.

4. **Function of Purkinje Fibers**:
- The Purkinje fibers distribute the electrical impulse throughout the ventricles, causing them to contract and pump blood to the lungs and the rest of the body.

5. **Conclusion**:
- Therefore, the Bundle of His passes the stimulus for contraction to the Purkinje fibers.

### Final Answer:
The Bundle of His passes the stimulus for contraction to the **Purkinje fibers**.