White matter is best described as?

White matter is best described as?

• A. accumulation of axons within the CNS with a fatty myelin sheath
• B. accumulation of neuron cell bodies in the CNS
• C. collection of axons in the PNS
• D. unmyelinated fibers in the CNS

Answer: (A)

White matter in the CNS is primarily made up of axons that are coated with a fatty myelin sheath. This myelin, produced by oligodendrocytes in the CNS, speeds up electrical signaling along those axons, allowing rapid communication between different brain regions and between the brain and spinal cord. The lipids in myelin give white matter its characteristic light appearance, which is why this description—an accumulation of axons within the CNS with a fatty myelin sheath—best fits white matter. In contrast, gray matter mostly contains neuron cell bodies and dendrites and lacks the heavy myelin content, while the CNS contains axons, not in the peripheral nervous system nerves, and unmyelinated fibers would not define white matter.

White matter in the CNS is primarily made up of axons that are coated with a fatty myelin sheath. This myelin, produced by oligodendrocytes in the CNS, speeds up electrical signaling along those axons, allowing rapid communication between different brain regions and between the brain and spinal cord. The lipids in myelin give white matter its characteristic light appearance, which is why this description—an accumulation of axons within the CNS with a fatty myelin sheath—best fits white matter. In contrast, gray matter mostly contains neuron cell bodies and dendrites and lacks the heavy myelin content, while the CNS contains axons, not in the peripheral nervous system nerves, and unmyelinated fibers would not define white matter.