Pathological pain of peripheral origin
This form of pathological pain occurs in chronic
stimulation of pain receptors (nociceptors), damaged nociceptive fibers, spinal
ganglia and dorsal root. These structures are often a source of intense and
constant nociceptive stimulation. Nociceptors are activated in chronic
inflammation (such as arthritis), the action of the decay products of tissues
(eg, in tumors), and others. Chronically damageable (for example, when squeezed
scars, overgrown bone and so forth.) And regenerating the sensory nerves,
degenerative changed (under the action of various hazards, endocrinopathy) and
demyelinated fibers are very sensitive to various humoral effects, even those
for which they do not react under normal conditions (for example, to the action
of epinephrine, K +, etc.). Sites such fibers are ectopic source of constant
and significant nociceptive stimulation.
A special role is played by such a source neuroma
- the formation of randomly overgrown nerve fibers, which occurs when they are
disordered and difficulty increase. These endings are sensitive to a variety of
mechanical, thermal, chemical and endogenous factors (eg, catecholamines).
Therefore, the pain attacks with neuroma, as well as nerve damage can be
triggered by different factors (for example, emotional stress, adrenaline
action).
Nociceptive stimulation from the periphery of
attack may cause pain if she overcomes the so-called "gating control"
in the rear horns (Melzak, wall) consisting of a brake unit substantia
gelatinosa neurons. These neurons control the flow entering the posterior horns
and the ascending nociceptive stimulation. This effect can occur when intense
afferent stimulation or by brake failure "gate-control."
Post Comment
No comments