Heart is innervated by :

Options

A. Vagus
B. Trigeminal
C. Facial
D. Glossopharyngeal

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the innervation of the heart, which refers to the nerves that supply the heart and control its functions.

2. **Identifying the Nerves**: The heart is primarily innervated by two types of fibers: parasympathetic and sympathetic fibers. The parasympathetic fibers come from the vagus nerve, while the sympathetic fibers come from the sympathetic nervous system.

3. **Analyzing the Options**:
- **Option 1: Vagus Nerve**: This is the correct answer. The vagus nerve (cranial nerve X) is responsible for parasympathetic innervation of the heart. The right vagus nerve innervates the sinoatrial (SA) node, and the left vagus nerve innervates the atrioventricular (AV) node.
- **Option 2: Trigeminal Nerve**: This option is incorrect. The trigeminal nerve (cranial nerve V) is primarily responsible for sensation in the face and motor functions such as biting and chewing.
- **Option 3: Facial Nerve**: This option is also incorrect. The facial nerve (cranial nerve VII) controls the muscles of facial expression and does not innervate the heart.
- **Option 4: Glossopharyngeal Nerve**: This option is incorrect as well. The glossopharyngeal nerve (cranial nerve IX) is involved in taste and the swallowing reflex, not in heart innervation.

4. **Conclusion**: Based on the analysis of the options, the correct answer is **Option 1: Vagus Nerve**.

### Final Answer:
The heart is innervated by the **vagus nerve** (Option 1).

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