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A grey column is any one of three ridge-like bodies of neural tissue called grey matter that's found in the spinal cord and extends lengthwise along the middle of both halves of it. It's sometimes called the grey horn because it has a horn-like appearance when the spinal cord is cut into transverse sections. The individual names for the grey columns are the anterior, lateral, and posterior grey columns. Each grey column is responsible for sending different types of information to the brain for processing.
The heavily ridged outer layer of the brain, called the cerebral cortex, is made up of several layers of neural tissue called grey matter. This tissue derives its name from the color it takes on after postmortem preservation. Grey matter is actually a pinkish beige in live tissue and is an important part of the central nervous system.
The nerve fibers of grey matter lack a myelin sheath, which is a covering that envelopes nerve fibers and aids in the transmission of nerve impulses. The whitish myelin sheath is responsible for the color of white matter, which is the layer of neural tissue located beneath the grey matter. White matter is pinkish white in living tissue and turns white after postmortem preservation.
The spinal column, also known as the backbone, spine, and vertebral column, is the protective bony casing that houses the spinal cord, which is a long thin bundle of nerve tissue that extends from the brain. The spinal cord begins at the occipital bone, which is a cranial bone located at the back of the human skull, and extends down the back and ends between the first and second lumbar vertebrae, which are located in the small of the back, above the hips. The vertebral column continues on to the sacral region, which is behind and below the hips. The spinal cord and the brain together make up the central nervous system.
Each grey column can be identified by its placement in the spinal cord. Closest to the front of the spine is the anterior gray column, which is also called the ventral horn and the ventral grey column. The anterior grey column is responsible for innervating skeletal muscles. Nearer to the back of the spine is the posterior grey column, also called the dorsal horn. The posterior grey column relays touch-related information to the brain. The lateral grey column is located between the anterior and posterior grey columns and is also called the lateral horn or the intermediate column. It is only found in the thoracic, or chest, and part of the lumbar, or lower back, regions and is connected to the sympathetic nervous system, which controls the body's internal organs.
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