Final answer:
The spinal cord connects the brain to the body, with white matter consisting of tracts for sensory and motor signals and gray matter containing neuron cell bodies and interneurons. Roots connect the spinal nerves to the cord, facilitating communication between the CNS and the body.
Step-by-step explanation:
The spinal cord is a critical structure within the central nervous system that enables communication between the brain and body. The white matter of the spinal cord consists of myelinated axons that form tracts. These tracts are responsible for the transmission of sensory (ascending) and motor (descending) signals. The gray matter processes information and directs impulses through the correct tracts. Spinal nerves emerge from the spinal cord through roots. These roots merge on each side of the spinal cord to form the spinal nerves that connect the central nervous system to the peripheral nervous system.
Collectively, the spinal nerves facilitate the crucial functions of sensory perception and motor control. White matter is organized into columns along the spinal cord. The posterior columns contain ascending tracts whereas anterior and lateral columns carry both ascending and descending tracts. This organization reflects the division of labor within the spinal cord for relaying information to and from the brain.