White matter consists of ______ and gray matter consists of _____.

• A. neuron cell bodies; myelinated axons
• B. myelinated axons; neuron cell bodies
• C. unmyelinated axons; dendrites
• D. dendrites; unmyelinated axons

Answer: (B)

Verified step by step guidance

1. Step 1: Begin by understanding the structural and functional differences between white matter and gray matter in the nervous system. White matter primarily consists of myelinated axons, which are responsible for transmitting signals over long distances. Gray matter, on the other hand, is composed mainly of neuron cell bodies, dendrites, and unmyelinated axons, which are involved in processing and integrating information.
2. Step 2: Review the anatomy of the central nervous system (CNS). White matter is typically found in deeper regions of the brain and spinal cord, while gray matter is located on the surface of the brain (cortex) and in specific areas such as the basal ganglia and spinal cord horns.
3. Step 3: Analyze the options provided in the question. The correct pairing should reflect the composition of white matter (myelinated axons) and gray matter (neuron cell bodies). Eliminate options that do not align with the anatomical and physiological characteristics of these structures.
4. Step 4: Recall the role of myelin in white matter. Myelin is a fatty substance that insulates axons, allowing for faster signal transmission. This is a key feature distinguishing white matter from gray matter, which lacks significant myelination.
5. Step 5: Confirm the correct answer by matching the descriptions to the appropriate terms. White matter consists of myelinated axons, and gray matter consists of neuron cell bodies, dendrites, and unmyelinated axons. This aligns with the correct answer provided in the question.