PHYSIOLOGY - somatosensory system Flashcards
where are the 1st order sensory neurons
PNS
synapses in dorsal root ganglia (in spinal cord)
where are the 2nd order sensory neurons
dorsal horn of spinal cord/brainstem nuclei
where are the 3rd order sensory neurons
thalamic nuclei
where do the 3rd order sensory neurons end up
somatosensory cortex
by what method is info passed on from one sensory neuron to another
contrast enhancement
by what method does a neurone switch off the neurons next to it (lateral to it) to make the stimulus seem sharper
lateral inhibition
what do nociceptors pick up
are they low or high threshold
pain
high threshold
what are the 2 types of temperature sensors
which is high threshold and which is low threshold
thermal nociceptors - high threshold
thermoreceptors - low threshold
what do pruprioceptors pick up
itch
what do proprioceptors pick up
joint and muscle position sense
what happens to APs when there is a high intensity stimulus in comparison to a low intensity stimulus
more APs
thicker myelination = …. APs
faster or slower
faster
what is the definition of a receptive field
the area of skin supplied by one nerve
what is a type 1 receptive field
where in the body is this an example of
when there are lots of small receptive fields
hands
what is a type 2 receptive field
where in the body is this an example of
how can this be tested (to differentiate it from a type 1 receptive field)
when there are fewer larger receptive fields
back
get someone to close their eyes and touch their back with 2 pins = they will only feel one
