NS VII Pain and Temperature Sensations Flashcards
when is body temperature the lowest
at 6 am
where are thermal receptors found
on free nerve endings in the skin, hypothalamus, spinal cord, and deep tissues
are cool or warm receptors more numerous
there are 3-10 times as many cool receptors
what are nociceptors activated by
extreme cold or heat
what fibers transmit warm and cool signals
C fibers and A Delta
what type of receptors are used in thermal sensation
TRP channels
what does temperature do to the rate of intracellular chemical reactions
increases it
what receptor does menthol activate and what temps
TRPM8 at cooler temperatures
what receptor does capsaicin activate and what temps
TRPV1 at warmer temps
how would you describe cold pain
tickling, pricking, aching, burning, numbing
how would you describe hot pain
sharp, pricking, stinging, burning, throbbing
what happens to cold/pain fibers if skin reaches freezing
they are no longer stimulated
what is the average skin temp
34-35 degrees C
at average skin temp are cool receptors or warm receptors activated more
equal
what happens at 45 degrees celcius of skin
heat/pain fibers are activated and sometimes cold fibers are activated too called paradoxical cold
do thermoreceptors adapt
almost but never completely
are thermoreceptors sensitive
very sensitive to changes in temperature
what happens to sensation when temperature reaches one of the pain thresholds
the sensation becomes more persistent throughout the stimulus
are nociceptors tonic or phasic
tonic
when are warm and cool receptors best able to detect a change
at the mid range of their temperature sensitivity
what happens to receptors as temperature increases
more receptors are activated and perception is increased
- increased rate of thermal receptors firing
the greater the area of skin affected by a thermal stimulus the greater______
the number of receptors, receptive fields, and first order neurons, and greater perceived sensation
is there are greater or lesser ability for detection of a temperature stimulus if a large region is activated
greaters
what receptor types are sensitive to chemicals
-vanilloid receptor subtype
- cold menthol receptor type 1 (CMR1/TRPM8)