Which sensory nerve is stimulated to produce laryngospasm?

The internal branch of the superior laryngeal nerve is responsible for conveying sensory information from the laryngeal mucosa above the vocal cords. When this nerve is stimulated, it can trigger a laryngospasm, which is an involuntary contraction of the vocal cords that can lead to difficulty in breathing or speaking.

This laryngeal reflex serves as a protective mechanism to prevent foreign substances from entering the trachea and lungs, emphasizing its important role in airway protection. The stimulation of this specific sensory nerve, therefore, is directly linked to the reflex action of laryngospasm, making it the correct answer to this question. Other nerves listed, while they do have sensory functions, do not specifically relate to the reflex arc responsible for laryngospasm. For example, the vagus nerve has broader functions and innervates other structures, but it is not the primary driver of the sensory input that leads to this specific response.