NROC64H3 Study Guide - Substantia Gelatinosa Of Rolando, Group C Nerve Fiber, Royal Electrical And Mechanical Engineers
22 views3 pages
somatosensation depends strongly on nociceptors besides mechanoreceptors
noiceceptors: free, branching, unmyelinated nerve endings that signal the body tissue is
being damaged or is at risk of becoming damaged.
the apth taken from nociceptors is diff from path taken taken ny mechanoreceptors
--> therefore, expereince elicited by activation of these 2 pathways are diff
selective activation of nociceptors leads to conscious experience of pain. pain is vital for
nociception and pain are not the same thing.
Pain- is the feeling or perception of irritation,sore,stinging etc
Nociception - is the sensory process that provides the signals that trigger pain
noc can fire away widly and continually, pain may come and go. vice versa: pain
agonizing without activity in noc
more than any other sensory systems, the cog qualities of noc can be controlled from
within brain itself.
Nociceptors and the Transduction of Painful Stimuli
noc are activated by stimuli that have the potential to cause tissue damage
tissue damage could be caused bystrong mechanical stimulation, temp extremes,
oxygen deprivation and exposure to certain chemicals
membrane of nociceptors contain channels that are activated by these type of stimuli
simple stretching or bending activates mechanically gated ion channels> causes cell to
depolarize and fire AP
damaged cells at site of injury can release number of other chemicals that can cause
channels on the nociceptor membrane to open i.e proteases
protease can break down extracellular peptide callled kininogen to form bradykinin
bradukinin binds to specific receptor substances that can activate ion conductances in
sensations of warmth and scalding are mediated by seperate neural mechanisms
running a marathon>anaeorobic respiration>buildup of lactic acid> excess H+ ions> these ions activate
H+ gated ion channels on nociceptors>causes excruciating dulll ache assoc with exercising.
Bee stinging> release of hsitamine> bind specific cell receptors on nociceptors>membrane depolarization
Types of nociceptors
transduction of painful stimuli occurs in free nerve endings of unmyelinated C fibers and lightly myelinated