Pain, temp, and GTOs Flashcards
what do free nerve endings respond to
pain
what are type of receptor are nociceptors and what do they respond to
free nerve endings - detect tissue damage
how are thermoreceptors activated
lipid is present in the closed channel
heat activates the channel and the lipid is lost
==
channel opens and ions can flow in
how do thermoreceptors and nociceptors respond to heat
thermoreceptors are active at lower temps but max out around 40-45deg (can’t tell a difference in warmth past here)
nociceptors only become active when the heat becomes tissue damaging (only way to tell somehting is hotter is that we’re getting more tissue damage)
what is capsaicin
lipid based molecule that is able to pass through the cell membrane
- makes spicy food “hot”
how does capsaicin work
causes vasodilation at the surface to dissipate the “heat” that’s being detected by thermoreceptors
what type of afferent innervates GTOs
type Ib afferent
what are GTOs the most sensitive to
active force production
why aren’t GTOs as sensitive to passive stretch (2N of passive needed vs 30-90 mN active needed)
passive stretch doesn’t put as much force on the tendon because the muscel will stretch first
- in active contraction, muscle fibres increase in stiffness and therefore the tendon stretches faster wtih less force
what is the GTO response during passive movement
very low discharge rate - low EMG activity
external force used to maintain motion
what is the GTO response during active movement
high discharge rate - high EMG activity
more active force = more GTO firing
what is the relationship between GTO discharge rate and force
linear relationship
- as force increases - GTO discharge rate increases
