疼痛的机制传导途径（Mechanism of pain transmission pathway）.docVIP

疼痛的机制传导途径（Mechanism of pain transmission pathway） The pain is caused by the stimulation of the damage or destruction of the tissues of the organism. It is a protective adaptation to the surrounding environment. This pain stimulation, after receiving the pain receptor, through different levels of pain transmission pathway, and finally reached the brain, causing pain sensation Three university says: special doctrine, type theory, gate control theory Basic transmission pathways (I) receptors and afferent nerve fibers Feel pain free nerve endings, it is widely distributed in each layer of the skin, capillaries and small vessels, connective tissue, visceral peritoneum and wall layer, submucosa, any damage outside or in vivo stimulation (physical or chemical), can cause local tissue damage, endogenous release of K+ H+, histamine, bradykinin, 5 - HT, Ach and substance P induced pain factor. These free nerve endings are particularly sensitive to chemical stimuli such as bradykinin, known as the chemical receptor (chemoceptor). The transmission of pain impulses of the fine fiber belongs to the A Delta and C fiber, and that the A delta fiber conduction and C fiber conduction tingling, burning. It must be noted, however, that not all A, Delta, and C fibers conduct only nociceptive stimulation, and they also carry sensory information such as touch, pressure, temperature, and cold. The pain is not only transmitted by fine fibers (A, delta or C fibers), but also by coarse fibers (A alpha fibers) that achieve a certain spatial and temporal configuration. (two) the transmission pathway of pain in the central nervous system The pain pathway is complex and still unclear. It is generally believed that the ascending pathway of the spinal cord associated with the transmission of pain is: 1. pain pathways in the trunk and limbs 1) fine fiber new Ridge Hill beam of the peripheral nerve into the spinal cord by lateral root, and then in the corner after the substitution, then a fiber upward