Transcript Nociceptive system

Somatic sensory analyzer
• Also different changes in
human organism
followed by pain are
observed: increase of
muscle tone,
accelerated heartbeat,
increase of blood
pressure, intensification
of sweating, dilatation of
pupils and elevation of
glucose and cuprum
level in plasma,
activation of hemostasis.
• It considered to cause
the majority of both
visceral and biochemical
reactions by excitation
of sympathetic nervous
system, which is
presented by neurons of
hypothalamus,
hypophisis and cells in
medullar substance of
adrenal glands.
• Afferent nociceptive impulses
are collected into central
nervous system by two kinds
of nervous fibers: quick adelta myelinated nerve fibers
and C-fibers without myelin.
• The ascending fibers are
included in spinothalamic
tract, which passes through
the spinal cord and reach
medulla oblongata. Here
there are second order
sensory neurons of
spinomesencephalic tract.
• Fibers of spinothalamic tract
synapse with third-order
neurons in the thalamus,
which in turn project to the
postcentral gyrus of the
contralateral cerebral
hemisphere.
Location of pathway
terminations
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