Which structure transmits somatic sensory information from the body to the spinal cord?

• A. Dorsal root fibers carrying somatic sensory information to the spinal cord (via dorsal roots and dorsal root ganglia)
• B. Ventral root fibers carrying motor information to muscles
• C. Cranial nerves responsible for taste
• D. Spinal interneurons in the dorsal horn

Answer: (A)

Somatic sensory information from the body enters the spinal cord through afferent fibers in the dorsal roots, with their cell bodies located in the dorsal root ganglia. These dorsal root fibers carry touch, proprioception, pain, and temperature signals into the spinal cord and may synapse in the dorsal horn to start processing before ascending to higher centers. The ventral roots, on the other hand, transmit motor commands from the spinal cord to muscles, not sensory data. Gustatory (taste) information travels via cranial nerves and reaches the brainstem, not into the spinal cord from the body. Spinal interneurons in the dorsal horn are involved in processing and local reflex circuits, not the direct transmission of sensory signals from the body to the spinal cord.