Question

Hot water bottle relieves pain of abdominal spasm by:

• A. Stimulation of adrenergic fibers
• B. Stimulation of cholinergic fibers
• C. Inhibition of cold receptors
• D. Inhibition of heat receptors

Hint:

Spasm relief means smooth muscle relaxation, which in the gut is the adrenergic effect.

Answer 1

The Correct Option is A

Step 1: Abdominal cramp pain comes from spasm of the smooth muscle in the gut wall. Relief means relaxing that muscle and damping the pain signals.
Step 2: Applying surface heat with a hot water bottle warms the abdominal wall and the underlying viscera. Local warmth promotes smooth muscle relaxation and increases blood flow, which helps wash out the pain-producing metabolites of the cramp.
Step 3: In the gut, sympathetic (adrenergic) activity inhibits motility and relaxes smooth muscle, whereas parasympathetic (cholinergic) activity increases contraction. So a response that eases spasm aligns with an adrenergic, muscle-relaxing effect, while cholinergic stimulation would worsen the spasm. This is why option B is wrong.
Step 4: Heat also reduces pain by counterirritation, a gate-control type mechanism in which warm-sensitive input dampens the transmission of pain. Heat does not work by inhibiting cold receptors (C) or by inhibiting heat receptors (D); in fact heat receptors are stimulated, not inhibited.
Note on the key: The recalled answer key is A. Of the four options offered, stimulation of adrenergic fibres is the choice consistent with smooth muscle relaxation and spasm relief, so the printed key is retained.
Conclusion: Answer is option A.