Gray matter of the nervous system differs from white matter in that ____________.

• A. gray matter consists mainly of glial cells, while white matter consists mainly of dendrites
• B. gray matter is found only in the peripheral nervous system, while white matter is found only in the central nervous system
• C. gray matter transmits signals faster than white matter due to the presence of myelin
• D. gray matter primarily contains neuronal cell bodies, while white matter is mainly composed of myelinated axons

Answer: (D)

Verified step by step guidance

1. Understand the basic composition of gray matter and white matter in the nervous system: gray matter primarily contains neuronal cell bodies, dendrites, and unmyelinated axons, while white matter mainly consists of myelinated axons.
2. Recognize that myelin is a fatty substance that surrounds axons in white matter, which helps increase the speed of electrical signal transmission.
3. Note that gray matter is involved in processing and interpreting information because it contains the cell bodies where synapses occur, whereas white matter is responsible for communication between different brain regions through its myelinated axons.
4. Identify that gray matter is found in regions such as the cerebral cortex and spinal cord's central regions, while white matter is located beneath the gray matter in the brain and surrounds the gray matter in the spinal cord.
5. Conclude that the key difference is that gray matter primarily contains neuronal cell bodies, making it the site of processing, while white matter is mainly composed of myelinated axons, facilitating faster signal transmission across different parts of the nervous system.