Final answer:
A dorsal root ganglion is the collection of cell bodies of the sensory neurons in the somatic PNS, with one ganglion for each spinal nerve, relaying sensory information to the spinal cord.
Step-by-step explanation:
The collection of cell bodies of the sensory neurons that are part of the somatic Peripheral Nervous System (PNS) is called a dorsal root ganglion. Each dorsal root ganglion is associated with a spinal nerve and contains the cell bodies of sensory neurons. These neurons are unipolar and have axons that extend from sensory endings in the skin, muscles, and other sensory organs into the Central Nervous System (CNS) through the dorsal nerve root. The ganglia act as relay points, with the dorsal root ganglia specifically relaying sensory information from the body to the spinal cord.