A vasovagal event is due to stimulation of which nerve causing bradycardia and hypotension?

A vasovagal event is due to stimulation of which nerve causing bradycardia and hypotension?

• A. Vagus nerve
• B. Sciatic nerve
• C. Phrenic nerve
• D. Median nerve

Answer: (A)

The main concept is parasympathetic control of the heart via the vagus nerve. A vasovagal event arises when the vagus nerve increases parasympathetic output to the heart, causing bradycardia (slower heart rate) and, together with reflex vasodilation, a drop in systemic vascular resistance leading to hypotension and potential syncope. The other nerves—sciatic, phrenic, and median—do not regulate heart rate or vascular tone in this reflex; they are involved in motor and sensory innervation of the limbs or diaphragm, not autonomic control of the heart. So the nerve responsible for this bradycardic and hypotensive response is the vagus nerve.

The main concept is parasympathetic control of the heart via the vagus nerve. A vasovagal event arises when the vagus nerve increases parasympathetic output to the heart, causing bradycardia (slower heart rate) and, together with reflex vasodilation, a drop in systemic vascular resistance leading to hypotension and potential syncope. The other nerves—sciatic, phrenic, and median—do not regulate heart rate or vascular tone in this reflex; they are involved in motor and sensory innervation of the limbs or diaphragm, not autonomic control of the heart. So the nerve responsible for this bradycardic and hypotensive response is the vagus nerve.