spinal cord


spinal cord

noun

: the large group of nerves which runs through the center of the spine and carries messages between the brain and the rest of the body

Full Definition of SPINAL CORD

:  the cord of nervous tissue that extends from the brain lengthwise along the back in the vertebral canal, gives off the pairs of spinal nerves, carries impulses to and from the brain, and serves as a center for initiating and coordinating many reflex acts — see brain illustration

First Known Use of SPINAL CORD

1834

spinal cord

noun    (Medical Dictionary)

Medical Definition of SPINAL CORD

: the thick longitudinal cord of nervous tissue that in vertebrates extends along the back dorsal to the bodies of the vertebrae and is enclosed in the vertebral canal formed by their neural arches, is continuous anteriorly with the medulla oblongata, gives off at intervals pairs of spinal nerves to the various parts of the trunk and limbs, serves not only as a pathway for nervous impulses to and from the brain but as a center for carrying out and coordinating many reflex actions independently of the brain, and is composed largely of white matter arranged in columns and tracts of longitudinal fibers about a large central core of gray matter somewhat H-shaped in cross section and pierced centrally by a small longitudinal canal continuous with the ventricles of the brain—called also medulla spinalis

Illustration of SPINAL CORD

spinal cord

noun    (Concise Encyclopedia)

Section of a spinal cord. The anterior horn of the gray matter contains cell bodies from which the …—© Merriam-Webster Inc.

In vertebrates, the body's major nerve tract. In humans it is about 18 in. (45 cm) long, running from the base of the brain through the vertebral column. It is covered by the meninges and cushioned by cerebrospinal fluid. It connects the peripheral nervous system (outside the brain and spinal cord) to the brain. The spinal cord and the brain constitute the central nervous system. Sensory impulses reach the brain via the spinal cord, and impulses from the brain travel down the spinal cord to motor neurons, which reach the body's muscles and glands via the peripheral nerves. The peripheral nerves are connected to the spinal cord via the spinal nerves. In humans there are 31 pairs of spinal nerves containing both sensory and motor fibres, which originate in the spinal cord and pass out between the vertebrae. These nerves branch and relay motor impulses to all parts of the body. Injury to the spinal cord may result in loss of communication between the brain and outlying parts and cause paralysis, loss of sensation, or weakness in the parts of the body served by areas below the injured region. Because nerve cells and fibres are unable to regenerate themselves, the effects are usually permanent.

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