Natural analgesia occurs when

Question

Quizplus · Accepted Answer

The periaquaductal gray matter stimulates interneurons in the dorsal horn to release endogenous opiates, which then bind to receptors on afferent pain fibers, resulting in natural analgesia. Therefore, option E is the correct answer. Option A is incorrect because endogenous opiates bind to receptors on afferent pain fibers, not P-substance. Option B is incorrect because endogenous opiates do not bind to nociceptors. Option C is incorrect because the periaquaductal gray matter inhibits afferent pain fibers in the spinal cord, not stimulates them. Option D is incorrect because endogenous opiates do not bind to excitatory interneurons, but rather to receptors on afferent pain fibers.

Natural Analgesia Occurs When