L2 Touch and Pain Flashcards
What is the sematosensory system?
a network of neurons that helps recognize objects, textures, and generate sensory-motor feedback
What types of receptors are mechanoreceptors?
Merkel cells
Meissner corpuscle
Ruffini corpuscle
Pacinian corpuscle
free nerve ending
What types of receptors are thermoreceptors?
Free nerve endings
What types of receptors are nociceptors?
Free nerve endings
All mechanoreceptors are A beta fiber types except which one? What fiber is it?
Free nerve endings ; C fibers
Warmth perceiving receptors are what type of fiber?
C
Cold perceiving receptors are what type of fiber?
A delta
What are merkel cells role in perception?
pressure, form, texture
What are meissner corpuscle’s role in perception?
motion,flutter
What are ruffini corpuscle’s role in perception?
stretch
What are pacinian corpuscle role in perception?
vibration
What are free nerve endings role in perception?
pressure
What are Adelta free nerve endings role in perception?
sharp localized pain
What are unmyelinated C free nerve endings role in perception?
burning
What are the two receptors in the superficial layer?
Meissner corpuscle
Merkel discs
What are the two receptors in the deep layer?
Ruffini corpuscle
Pacinian corpuscle
How do you measure receptive field?
two point discrimination
What is the relationship b/n receptive field size and ability to distinguish b/n sensations?
the smaller the receptive field, the more distinction ability
like in hands and face
How is cutaneous sensory transduced?
as membrane stretches, ion channels open
What are the rapidly adapting receptors?
Meissner’s corpuscle
Pacinian corpuscle
What are the slowly adapting receptors?
ruffini’s corpuscle
merkel disks
What is the reason for receptor adaption?
to allow for texture and pattern perception
How does somatosensory info enter the CNS?
vis dorsal root ganglia into dorsal root
What column does mechanosensory travel up in the spinal cord?
post./dorsal column
What column does pain and temp. travel up in the spinal cord?
lateral column
Where does crossing over occur in the medial lemniscal system?
arcuate fibers in caudal medulla
This is also known as the dorsal column
Mechanosensory receptors from the upper body travel up which tract?
cunate
Mechanosensory receptors from the lower body travel up which tract?
gracile
Where do mechanosensory receptors from the upper body synapse?
cunate nucleus
Where do mechanosensory receptors from the lower body synapse?
gracile nucleus
What sense is the Ventral post. lat. nucleus of the thalamus responsible for?
Sensory for body
CHECK THIS
(L)ateral Nucleus = (L)otion for the BODY
What sense is the Ventral post. med. nucleus of the thalamus responsible for?
sensory for the head/face
(M)edial = (M)akeup for the FACE
T/F Different portions of the brain are dedicated to body parts based on density of info
True
Example = the lips and hands have a lot of sensory density so they take a larger part of the brain than your torso.
VR-1 (TPVR-1) receptor is a receptor for what?
capsaicin
Where are VR-1 (TPVR-1) receptors found?
intracellularly
T/F there technically are pain receptors in the body?
False
there are no pain receptors in the body
What Nociceptors respond to?
intense and possibly harmful stimuli
What type of pain are C fiber associated w?
dull, longer lasting pain
Where do Nociceptors cross over
anterior white commissure
What would be the effects of a left lower thoracic lesion?
reduced temp and pain sensation on right
reduced two-point discrimination, vibration, and proprioception on left
What is lissauer’s tract?
2-3 segments above and below the DREZ (dorsal root entry zone)
How is nociceptive perception maintained in case of injury?
lissauer’s tract
What tract is assoc w/ pain reception
anterolateral (neospinothalamic)
Where are pain receptors synapsed at?
Ventral post lat nucleus of thalamus
Where does pain and temp info enter the spinal cord for upper body?
cervical spinal cord
Where does pain and temp info enter the spinal cord for lower body?
lumbar spinal cord
Where does pain and temp info enter the brainstem for the face?
midpons
Where does pain and temp info synapse for the face?
VPMN of thalamus
Ant. cingulate is the target for what?
avoidance/emotional component that drives behavioral responses
Amygdala is the target for what?
negative emotion
Hypothalamus is the target for what?
fight or flight
Superior colliculus is the target for what?
visually directs is to source of paine
Reticular formation is the target for what?
arousal to respond to pain
Periaqueductal gray is the target for what?
pain modulation
Where do spinotectal fiber synapse?
PAG
Where does the PAG project to?
Raphe nucleus
Lateral tegmental nucleus
Where do the raphe nucleus and lateral tegmental nucleus synapse?
enkephalinergic interneurons
What is the role of the enkephalinergic interneurons?
release endogenous opioids to modulate pain
like a negative feedback loop
perception of normally non-painful stimuli as being painful is called?
allodynia
Painful stimuli that is perceived to be more painful than expected is called?
hyperalgesia
What causes allodynia and hyperalgesia?
peripheral sensitization
centra; sensitization
Release of neuropeptides from C fibers causes?
local sensitization