Somatosensation Flashcards
Where are sensory neurons mainly located in the spinal cord?
Dorsal ganglia
What are the two categories for somatosensory receptors in the dorsal root ganglia?
Noxious and innocuous
What sense(s) do Noxious receptors sense and what type of receptor is it?
Heat, Cold, Pressure, Chemicals
Nociceptor
What sense(s) do Innocuous receptors sense and what is the specific receptor type?
Touch
Mechanoreceptor
What is the general pathway for somatosensation
sensory fiber activation»>processing in spinal cord and brain»>perception of pain/touch/itch/etc.
interception vs proprioception
intero: sensations of internal organs
proprio: sense of outer body (balance, spatial awareness)
List somatosensory fibers from thickest/myelinated to smallest/unmyelinated
Aα»>Aβ»>Aδ»>C(unmyelinated)
What are Piezos and what do they do?
mechanotransduction channels that help transduce mechanical energy into and action potential for the innocuous sensation of touch
Why can animal survive without Piezo2 and not Piezo1?
Piezo1 is responsible for vascular development and bladder mechanosensation
Piezo2 only contributes to the sensations of pain and other touch sensitivity
What are the types of pain
Nociceptive (transient, reversible)
Inflammatory (long-lasting, reversible)
Neuropathic (persistent, irreversible)
What are the types of nociceptors and what stimuli do they respond to?
Aδ and C
They respond to thermal, chemical, and polymodal stimuli
What is the general mechanism of chronic pain?
transduction (damage) >transmission (depolarization) >modulation (sensation)
What are the two types of itch?
chemical and mechanical
what is another term for itch
pruriception
Describe the relationship between Ucn3+ neuron, NYP+ interneuron, TLR5+, and LTMRs (low-threshold mechanoreceptors)
LTMRs and TLR5+ give inputs to Ucn3+ which transmits mechanical itch. NYP+ can inhibit mechanical itch when acting on Ucn3+
