[PHYSIO] Spinothalamic tract sensations Flashcards
sensation
information about environment obtained by sensory receptors
perception
brain selects, organizes, interprets sensations
sensory unit
sensory axon + all its peripheral branches
receptive field
spatial distribution area from which stimulus produces response
general sensations are classified into
somatic
visceral
special sensations
vision
smell
taste
hearing
(+somatic)
organic sensations
thirst
hunger
emotional sensations
fear
sadness
somatic sensations are classified into
cutaneous
deep
mixed
cutaneous sensations
touch
temperature
pain
deep sensations
deep pain
proprioception
mixed sensations
vibration
stereognosis
stereognosis
perception & recognition of an object in absence of visual & auditory info
tactile mechanoreceptive sensations
touch
pressure
vibration
kinesthetic mechanoreceptive sensations
sense of position & movement
cortical sensations
sharply localized fine sensations
thalamic sensations
poorly localized crude sensations
slow pain
wide degrees of thermal sensations
crude touch
are…
thalamic sensations
fast pain
fine touch
vibration
fine degrees of thermal sensations
stereognosis
proprioception
deep pressure
cortical sensations
spinothalamic sensations (5)
pain
crude touch
thermal sensations
itch & tickle
sexual sensations
dorsal column sensations (5)
fine touch
deep pressure
vibration
stereognosis
proprioception
spinothalamic pathway alternative name
anterolateral system
spinothalamic pathway transmits
how?
crude touch
thermal signals
pain
by sequence of 3 order neurons
crude touch definition?
properties?
ability to detect contact w objects
non-discriminatory, poorly localized
receptors of crude touch
mechanoreceptors:
1) Free nerve endings
2) hair end organs
mechanism of stimulation of crude touch receptors
mechanical deformity
afferents of crude touch
A𝛿
C type fibers
ascending sensory pathway of crude touch
ventral ALS
higher perception site of crude touch
thalamus
adaptation of crude touch receptors
rapid
how to examine crude touch sensation
cotton wool test
tickle sensation
local repeated mechanical stimulation by light moving object
itch sensation
irritation sensation caused by histamine & kinins
may lead to scratch reflex
receptors of itch & tickle sensation
FNE
afferents of itch & tickle sensation
C type fibers
ascending sensory pathway of itch & tickle sensation
ventral ALS
higher perception site of itchy & tickle sensation
thalamus
thermal sensation receptors
Thermoreceptors:
hot—> FNE
cold—> FNE & Krause end bulb
mechanism of stimulation of thermoreceptors
conc. changes of metabolites—> (+)/(-) ion channels
TRP
transient receptor potential= ion channels
how are TRP activated
excess change in temp, above 43° C
this mediates pain sensation
distribution of thermoreceptors?
which receptors are more widely distributed?
in spots.
cold spots are more by 3-10 times
thermoreceptors are commonly found in
lips>hands>trunk
cold receptors range of stimulation
10-43° C
maximal at 25° C
hot receptors range of stimulation
30-50° C
maximal at 45° C
sensation felt at less than 15°C
cold pain
sensation felt at more than 45°C
hot pain (TRP)
sensation felt at 30-35° C
indifferent sensation
area of overlap
near body temp
protopathic sensations
sensations perceived by thalamus
epicritic sensations
sensations percieved by cortex
afferents of thermal sensations
warm—> C
Cold—> A𝛿 + C
ascending sensory pathway of thermal sensations
lateral ALS
higher perception site
thalamus + cortex
adaptation of thermoreceptors
moderate
hot>cold
how to examine theram sensation
two test tube test
paradoxical cold sensation
sensation of cold that occurs due to exposure to hot temperatures
paradoxical cold sensation occurs due to
rise of temperature above 40° —>sudden & rapid discharge of impulses from cold receptors