Skin and visceral ________ converge on the same neuron in the cord.

• A. receptors
• B. afferents
• C. interneurons
• D. efferents

Answer: (B)

Convergence of sensory information from different sources onto the same spinal cord neuron is a common way the nervous system integrates signals. In this case, sensory signals from the skin (somatic) and from visceral organs travel along afferent pathways to the spinal cord and can end up synapsing on the same neuron there. Afferents are the sensory neurons that carry information from receptors toward the central nervous system; they are the ones delivering these signals to the cord. The fact that both somatic and visceral afferents can feed into the same spinal neuron explains how visceral sensations can be perceived as coming from the skin region—a phenomenon known as referred pain.

Receptors are the peripheral ends that transduce stimuli but are not themselves the neurons carrying information into the spinal cord. Efferents are motor outputs leaving the CNS to muscles or glands, not pathways for bringing sensory information into the cord. Interneurons are cells inside the cord that can receive afferent input, but the statement focuses on the type of input (afferents) rather than the specific post-synaptic neuron type.