Gray matter of the brain

The brain and spinal cord can be grossly divided into gray matter and white matter. White matter is surrounding gray matter. White matter is made up of nerve fibers.

On cross section of the spinal cord, the gray matter has a butterfly-like appearance and contains nerve cell bodies. The gray mater contains synapses between sensory, motor and interneurons.

In the gray matter of the cord, connections can be made between incoming and outgoing nerve fibers which provide the basis for reflex action. The spinal cord functions as both a reflex center and a conduction pathway to and from the brain.

Most of the brain functions are believed to be located in the gray matter and to occupy a given area of the gray matter layer, called the cortex or cortical surface.

Gray matter centers in the brain stem control many vital body functions without conscious involvement or control by the cerebrum.

Among these functions are the heart and respiration rates, blood pressure constriction and dilation of blood vessel, coughing and reflex activities of the digestive system such as vomiting.
Gray matter of the brain