A cross-section of the spinal cord consists of a butterfly-shaped region of gray matter at the center and surrounding areas of white matter, according to Bookshelf. A small hole exists in the middle of the gray matter, known as the central canal.
The gray matter of the spinal cord contains the cell bodies of lower motor neurons, informs the University of Minnesota. The structure is divided into the dorsal horn in the upper half and the ventral horn in the lower half. Axons carrying signals from peripheral nerves enter the spinal cord through the dorsal horn. Axons carrying signals to peripheral tissues, such as those for controlled and reflexive movements, leave through the ventral horn.
The white matter of the spinal cord is comprised of neuronal axons that form large bundles called funiculi, explains Bookshelf. The dorsal funiculus sits in the uppermost part of the spinal cord section and transmits sensory information from the body to the brain. The lateral fibers, located between the dorsal and ventral horn of the gray matter, relays signals from the brain to the lower motor neurons of the spinal cord. The ventral fibers are positioned below the ventral horn of the gray matter and carry both ascending and descending information.