Which of the following are considered normal central reflexes?

• A. Knee-jerk reflex
• B. Pupillary reflex
• C. Anal wink
• D. Cough, gag, swallow

Answer: (D)

Central reflexes are reflexes that are mediated by brainstem circuits rather than the spinal cord. Coughing, gagging, and swallowing fit this category because their reflex arcs rely on cranial nerves and brainstem nuclei to sense the stimulus and generate a protective response. For gag, the afferent limb comes from the glossopharyngeal nerve and the efferent limb uses the vagus nerve, with processing in the brainstem. The cough reflex involves the vagus too, with medullary centers coordinating the cough. Swallowing is a coordinated brainstem reflex involving multiple cranial nerves (including IX, X, and XII) to move the swallow together safely. In contrast, the knee-jerk reaction is a spinal stretch reflex, managed at the spinal cord level, and the anal wink is another spinal reflex involving sacral nerves. So the cough, gag, and swallow set reflects intact brainstem (central) reflex pathways.