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White matter is the tissue through which messages pass between different areas of grey matter within the central nervous system. The white matter is white because of the fatty substance (myelin) that surrounds the nerve fibers (axons). This myelin is found in almost all long nerve fibers, and acts as an electrical insulation.
The corticospinal tract is a white matter motor pathway starting at the cerebral cortex that terminates on lower motor neurons and interneurons in the spinal cord, controlling movements of the limbs and trunk. [1] There are more than one million neurons in the corticospinal tract, and they become myelinated usually in the first two years of life.
Sectional organization of spinal cord. The spinal cord is the main pathway for information connecting the brain and peripheral nervous system. [3] [4] Much shorter than its protecting spinal column, the human spinal cord originates in the brainstem, passes through the foramen magnum, and continues through to the conus medullaris near the second lumbar vertebra before terminating in a fibrous ...
Two of the five sensory modalities, pain and temperature, cross sides at the anterior white commissure, reaching the contralateral side about two vertebral levels rostral to their origin. The spinothalamic tract thus decussates very soon after entering the spinal cord, ascending in the spinal cord, contralateral to the side from where it ...
The white ramus communicans (pl.: rami communicantes) from Latin ramus (branch) and communicans (communicating) is the preganglionic sympathetic outflow nerve tract from the spinal cord. Each of the thoracic, and the first and second lumbar nerves contribute a white ramus communicans to the adjoining sympathetic ganglion , unlike the gray rami ...
In particular, the cell bodies of the spinal interneurons are found in the grey matter of the spinal cord, which also contains the motor neurons. In 1952, the grey matter of the cat's spinal cord was investigated, and it was shown to have ten distinct zones referred to as Rexed laminae. Eventually, the lamination pattern was also observed in ...
Saladin, Kenneth S. "The Spinal Cord, Spinal Nerves, and Somatic Reflexes." Anatomy & Physiology: The Unity of Form and Function. 6th ed. New York: McGraw-Hill, 2012. N. pag. Print. This article incorporates text in the public domain from page 759 of the 20th edition of Gray's Anatomy (1918)
The axons enter the spinal cord from the dorsal root ganglia and terminate on unknown second-order neurons in the posterior grey column. [2] The axons from the second-order neurons cross the midline and ascend as the spino-olivary tract in the white matter at the junction of the anterior and lateral columns. [2]