Final answer:
The white matter of the spinal cord contains both myelinated and unmyelinated nerve fibers, which are organized into columns and are crucial for transmitting neural signals.
Step-by-step explanation:
The white matter of the spinal cord contains both myelinated and unmyelinated nerve fibers. The myelinated axons are responsible for the white appearance of this matter due to the high lipid content of the myelin sheath. White matter facilitates the conduction of nerve impulses along ascending and descending tracts, conveying sensory information to the brain and motor commands from the brain to the rest of the body, respectively.
The white matter is organized into columns, such as the posterior, anterior, and lateral columns, which are comprised of different groups of myelinated and unmyelinated axons. These axons are bundled together, much like wires in a cable, and extend along the length of the spinal cord. White matter is essential for the efficient transmission of neural signals throughout the central nervous system.