Somatosensory System (3) Flashcards
what is the difference between glabrous and hairy skin
glabrous skin is hairless and has more receptors than hairy skin
what are the two main groups of somatic sensory receptors and where are they located
mechanoreceptors: responds to stimuli other than pain/temperature in the skin
nociceptors: responds to pain/temperature; also in the skin
what are mechanoreceptors sensitive to
bending/stretching of the skin
what are the two different somatosensory receptive fields
meissners corpuscles: small receptive field
pacinian corpuscles: large receptive field
what is somatosensory adaptation and how is it obtained
if a receptor adapts quickly, they will respond to only onset and offset stimuli
if a receptor adapts slowly, they will continue to respond to the stimuli throughout the entire stimulus
describe Aalpha receptors
proprioceptors, fastest conduction velocity, myelinated
describe Abeta receptors
mechanoreceptors, mid conduction velocity, myelinated
describe Adelta receptors
nociceptors, mid conduction velocity, myelinated
describe C receptors
nociceptors, slowest conduction velocity, not myelinated
what is the dermatone
the spinal cord of afferent innervation; cervical, thoracic, lumbar, sacral, determines which vertebrae each section of the body sends information to
describe the hapsis pathway!!
- dorsal root axon
- dorsal column
- dorsal column nuclei
(crosses to other side in brainstem/medulla) - medial lemniscus
- thalamus
- cerebral cortex
describe the nociception pathway!!
1. dorsal root axon (crosses to the other side in spinal cord) 2. lateral spinothalamic tract 3. thalamus 4. cerebral cortex
what sense can bypass the thalamus
smell
what is the somatosensory homunculus
every part of the body takes up a different amount of the brain; more neurons/brain is devoted to globous skin
what are nociceptors
receptors associated with pain and temperature
what is hyperalgesia
when the body is more sensitive to stimuli around an injured part of the body
describe referred pain
substantia gelatinosa neurons receive pain input from the skin in one area as well as an internal organ so the brain registers pain in both areas
what is the gate theory of pain (who is credited for it)
melzack and wall
hapsis input can inhibit pain input
what is descending innervation
serotonin and endorphin reduce pain chemically
what are the hot and cold receptors
hot: capsin
cold: methanol
true or false: thermoreceptors have static responses
falso
