Question

Gag reflex will be absent in which nerve injury?

• A. 5 and 10
• B. 9 and 10
• C. 10 and 12
• D. 7 and 9

Hint:

The gag reflex is absent in injuries involving the glossopharyngeal (IX) and vagus (X) nerves, as both are integral to the sensation and motor function of the reflex.

Answer 1

The Correct Option is B

In the anatomy of the human body, the gag reflex is an essential protective reflex that helps prevent choking. It involves two cranial nerves: the glossopharyngeal nerve (cranial nerve IX) and the vagus nerve (cranial nerve X). The glossopharyngeal nerve is primarily responsible for the sensory limb of the reflex, providing sensation to the mucosa of the pharynx. The vagus nerve manages the motor component, controlling the muscular contraction of the pharynx and the soft palate. An injury to any of these nerves can result in the absence of the gag reflex.

Given the options:

• 5 and 10
• 9 and 10
• 10 and 12
• 7 and 9

It is clear that both the glossopharyngeal (nerve IX) and the vagus (nerve X) are integral for the gag reflex. Hence, injury to these two nerves (9 and 10) would result in the absence of the reflex.