Which term describes a bulge on the posterior root containing tissue receiving and sending impulses?

• A. Interneuron
• B. Synapse
• C. Nucleus
• D. Ganglion

Answer: (D)

A dorsal root ganglion is a swelling along the posterior root of a spinal nerve that houses the cell bodies of sensory neurons. This bulge contains tissue that receives impulses from peripheral receptors and sends signals into the spinal cord via the central processes of those same neurons. That’s why the correct term is ganglion—the dorsal root ganglion is the cluster of neuron cell bodies outside the central nervous system on the posterior root.

Interneurons are neurons within the CNS that connect other neurons, so they aren’t described by a bulge on a spinal nerve root. A synapse is the junction between neurons, not a bodily swelling. A nucleus is a cluster of neuron cell bodies typically found in the CNS, not a swelling on a peripheral nerve root.