13 - Somatosensory System Flashcards
neurotransmission in all sensory neurone?
Excit [main NT: Glutamate]
different densities of myelination and what processes need them?
Aa [thickest]
- proprioceptors of skeletal muscle [GTO/MS]
Ab
- mechanoreceptors of skin
Ag
- pain/temperature
C
- temp/itch/pain
what is a receptive field?
- sensory nerve ending [axon] supplies RF
- RF contains mechanoreceptors etc
why do receptors only pick up a specific stimuli?
Adequate stimuli
- preffered stimulus they can transudce –> electrical energy
Threshold
- specific threshold stimulus must overcome
how is graded receptor potential generated?
[ basically how a receptor causes AP in the sensory neurone]
- stimulus in the receptor
- cause transduction channels open in nerve ending
- depolarisation
- graded receptor potential
- threshold reached to cause action potential
how is a slow adapted sensory receptor different to fast adapting receptors?
Slow
- receptor has slow response to stimuli
- stimuli removed - receptor response fall slowly
Fast
- receptor responds quickly to stimuli
- not a sustained response
3 types of sensory receptors?
thermo, mechano, nociceptors
myelination of axons that supply mechanoreceptors?
Ab myelination
4 types of mechanoreceptors and layers found in?
superficial
- merkell recep
- meissners recep
deep layer
- ruffinis corp
- Pacinian corp
which mechanoreceptors are slow adapting [what do they detect]?
- Merkel receptors - sustained light touch
- Ruffnis C - stretch and deep touch
which mechanoreceptors are fast adapting [what do they detect]?
- Meissners -light touch/vibrations
- Pacinian - poke/vibration
- hair receptors - light touch
structure of axons that supply thermoreceptors?
- C
- thermo are slow adapting!
why do some thermoreceptors detect hot or cold?
- adequate stimuli
- either to hot or cold
what do thermoreceptors have that allow them to detect hot or cold?
- TRP channels [+ ion entry]
- cause depolarisaton
how is cold detected by thermoreceptors?
- TRP-M8 channels
- @ 10-38
