Afferent entrances to the spinal cord

Afferent entrances to the spinal cord ( t.   e.   Inputs bearing inform a tion CNS) axons formed by the spinal neurons (spinnomozg on O) ganglia that lie outside of the spinal cord. The first group of spinal afferent inputs formed by sensitive fibers of cat about eye receives information from the proprioceptors of muscles, ligaments and tendons (proprioceptive sensitivity). The second group of afferent inputs carries information from skin receptors (tactile, pain, and temperature), t.   e.   is the entrance of skin exteroceptive feelings and body. The third group of afferent inputs carries information from VNU t nal bodies (vistserotseptivnaya sensitivity).

Spinal cord function. The spinal cord carries out two main functions – reflex and the introducer (one is to transfer lo n weed signals from the receptors of the skin, muscles, tendons, joints and within n their bodies to supraspinal structures and to the cerebral cortex, and the second is connected with the transmission of afferent brain signals brain to the ILO about the neurons and autonomic neurons of the spinal cord). At the same time it is possible g of vorit that contains components spinal cord motor, vegetative and tive and sensory systems in the brain and thus it executes the corresponding w boiling function (motor, sensory and autonomic).

Reflex function – is the realization of absolute motor and autonomic reflexes and developed on their basis sootvets t vuyuschih conditioned reflexes. Spinal cord implements such motor reflexes as miotaticheskogo or tendon, flexor, chesatel s nye reflex stepping movements, postural-tonic and Viscera of motor arising from stimulation visceral afferent nerves (in this case changes the tonic activity of the muscles of the chest and abdominal wall, as well as the extensor muscles of the back). On the basis of these unconditioned reflexes in the process of individual development of forms , conditioned motor reflexes are ruled.

Reflexes of the autonomic nervous system have their own characteristics. They arise when excited vistseroretseptorov and tactile those m -temperature, nociceptors and proprioceptors (muscle, dry of gangue and articular receptors). Excitation decree n GOVERNMENTAL receptors causes flow sensory impulses that nep about sredstvenno (or indirectly via intercalary neurons) excites vegetative no minutes spinal cord hand, localized in the side of its horns. By these neurons via axons second neurons found in autonomic ganglia , and s, the excitation body reaches and calls the appropriate effect, e.g., increased heart rate with no activation of the sympathetic minutes tron spinal cord or smooth muscle relaxation genital vessels upon excitation sacral parasympathetic neurons of Dep e la spinal cord. In general, with the participation of the spinal cord are realized such autonomic reflexes as vasomotor, cardiac, traheobro n hialnye, potootdelitelnye, motor and secretory reflexes pishch e nary tract, micturition reflex, defecation, sexual re p Lex and others. On the basis of these innate reflexes in individual s Foot of forming conditional autonomic reflexes.

Reflex activity of the spinal cord often proceeds against the background of and p radiation of excitation, which goes both along the spinal cord and inside the segment to the opposite side. The nature and degree of irradiation depend both on the location and strength of the stimulation, and on the excitability of the central apparatus of the spinal cord. This process involved interm and at precise neurons activating in normal circumstances mainly Motono minutes Rhone respective segments, which provides a more or less of g boundedness reflex reaction by the action of mild irritation of the receptive field. One characteristic of the reflex activity of the spinal cord (as well as other parts of the central nervous system) yavl I etsya strengthening reflex reactions with repeated stimuli (summation phenomenon), which can be seen as the result of increasing exc at gence working in neural systems. Increasing excitability tse n sweeping elements reflex arc after one afferent volley pulse lasts from several hundred milliseconds to several seconds. The important thing is that many spinal reflexes occur dostat hours but steadily. Therefore, the change and loss of spinal reflexes, n and Example knee reflex may be a diagnostic test for otse n ke functional state of the spinal cord. At the same time, the realization of some motor reflexes of the spinal cord in the process of ontogenesis is inhibited (for example, the flexor plantar reflex). Therefore, n about the phenomenon of such reflections in the later stages of ontogeny is si m ptomu spinal cord lesions.

local_offerevent_note April 19, 2019

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