Question

If the vagus nerve of a person is accidentally cut which of the following cannot happen?
A. Stimulation of gastric juice production
B. Reduced peristalsis
C. Aptyalism
D. Achlorhydria

Answer 1

Hint: It is a tenth cranial nerve. It has both sensory fibers and motor fibers but predominantly of motor fibers.

Complete answer: There are twelve cranial nerves:
1. Olfactory nerve, 2. The optic nerve, 3. Oculomotor nerve,
4. Trochlear nerve, 5. The trigeminal nerve, 6. Abducens nerve,
7. The facial nerve, 8. Vestibulocochlear nerve, 9. Glossopharyngeal nerve,
10. The vagus nerve, 11. Spinal accessory nerve, 12. Hypoglossal nerve.

The tenth nerve is the longest among all the cranial nerves because it passes from the neck and thorax to reach up to the abdomen. It is widely distributed in the body hence it is also called vagrant or wandering nerve.
The sensory part of the vagus nerve is distributed in the external meatus, sensation to heart, and abdominal viscera. The motor part is distributed in the muscles of the pharynx, soft palate, larynx. The parasympathetic part is distributed in the smooth muscles of the trachea, bronchi, gastrointestinal tract, and heart rhythm.
The vagus nerve causes stimulation of secretion of gastric juice in the stomach when it will get damaged it will cause a decrease in the secretion of gastric juice.
Aptyalism is the absence of secretion of saliva, it can occur due to damage to the glossopharyngeal nerve.
Peristalsis of the Gastrointestinal tract occurs due to the parasympathetic supply of the vagus nerve hence when it gets damaged it will cause a decrease in peristalsis.

Therefore the correct answer is A. Stimulation of gastric juice production.

Note: The vagus nerve can get damaged due to diabetes mellitus (diabetic neuropathy), or any accidental cut in surgery.