Central nervous system (central part) with c Toit of phylogenetically old spinal cord located in the spinal canal, and younger – brain, lying in the cranial cavity. The spinal cord is related and Tel’nov simple structure principle and expressed segmental organisms and tion. It provides connections of the brain with the periphery and performs segmental reflex activity. The spinal cord lies in the colloidal canal from the upper edge of the I cervical vertebra to the I – II lumbar region . go vertebra. Below the spinal cord passes into the brain cone, sell l zhayuschiysya a terminal thread which penetrates into the sacral canal and cp and ceases with the dura. The spinal cord is divided into five parts: neck (8 segments), the rib (12) and lumbar (5), the sacral (5) and to the n Chikova (1-3). Total – 31–33 segments. The length of the spinal cord in an adult varies from 40 to 45 cm, width – from 1 to 1.5 cm, and the weight is equal to an average of 35 g. The thickness of the spinal cord increases slightly from bottom to top. In zone clearly distinguished cross-sectional view of the spinal cord gray and white of the first substance. The white matter of the spinal cord is myelinated and partly amyelinated nerve fibers, as well as supporting nerve tissue – neuro g Leah and blood vessels. Gray matter is a collection of neurons with their processes that do not have a myelin sheath. There are also processes of those nerve cells that are located in other parts of the spinal cord and brain, as well as neuroglia and blood vessels. The gray matter is located in the center of the spinal cord and its shape resembles a butterfly with spread wings or the letter H. In the gray matter distinguish two side portions located in both n of the spinal cord Lovina and a transverse portion connecting them in the form y of one bridge. In the center of the gray matter, the central spinal cord passes through the brain canal, which at the top passes into the cavity of the 4th ventricle. K a zhdaya side portions of gray matter forms three projections – Front for d Nij and side. The protrusions throughout the spinal cord form gray pillars . Each of them in the cross sectional view of the spinal cord f of taking the name horn (respectively, front, rear and side). For d of horn operate mainly functions and sensory neurons comprise transmitting signals in overlying centers and CIMMYT m hexadecimal opposite side to the front structure and horns of the spinal about go brain. The front horn, due to the presence of these motor neurons and neurons perform the motor function – go down the way the central nervous system, causing the motor reactions, ending precisely on not th ronah anterior horn. Side horns are involved in the regulation of the vegetative functions of the body.
From each spinal segment extend two pairs of roots, cat on rye form connecting peripheral spinal nerves . The anterior and posterior roots of the same level and one side join to form the spinal nerve , which is therefore mixed. Ka x gives to a pair of spinal nerves (right and left) corresponds opred e lennomu portion – a segment of the spinal cord. Consequently, in the spinal mo h n has as many segments as pairs of spinal nerves.