Neurology (01/23) Ascending Sensory Systems Flashcards
cerebral blood flow is constant with regional changes due to what three things?
- autoregulation
- collaboration of brain and vessels
- cerebral vascular autonomics
one mechanism used to maintain constant cerebral blood flow that includes vessels being stretch sensitive and constricting under low pressure and dilating under high pressure
autoregulation
somatosensory receptors detect what three types of changes?
- mechanical
- chemical
- thermal
somatosensory receptors are ______ neurons
pseudounipolar
where are the cell bodies located for somatosensory receptors (pseudounipolar neurons)?
dorsal root ganglion or cranial nerve ganglion
somatosensory receptors have both a ____ process and a _____ process with an ending in the skin, muscle, or a joint
- CNS
- PNS
what are the two types of encapsulated receptors in the skin?
- pacinian corpuscles
- meissner corpuscles
for hairy skin, the receptor endings ____ ____ hairs
wrap around
hairless skin
glabrous
type of receptor in the skin that uses discriminative touch and is concentrated in finger tips. it uses A-beta (fast conducting) fibers
meisser corpuscle
type of receptor in the skin that uses discriminative touch and is used for fine detail (edges of objects, texture). it uses A-beta (fast conducting fibers)
merkel nerve ending
pathway of touch sensation in the posterior column
medial lemniscal pathway
the medial lemniscal pathway uses two point discrimination and is involved with _____ proprioception. it decussates in the _____ and relays info in the _____ thalamus. it ultimately terminates in the _____ _____
- conscious
- medulla
- lateral
- postcentral gyrus
spatial resolution correlates with number of _____ receptors
cutaneous
there are more meissner corpuscles and merkel endings in the finger tip than in the hand so two-point discrimination is more sensitive in the _____ ____
finger tip
type of receptor in the skin that is used to detect vibration (pressure). it is concentrated in the fingers and palm and uses A-beta (fast conducting) fibers
pacinian corpuscle
what three things do free nerve endings give the sensation of?
- pain
- crude touch
- temperature
for nocireceptors, thermoreceptors, and some mechanoreceptors, temperature sensitivity is due to _____ that open with a specific range of temperatures
channels
sharp prick or well-localized pain that has a short duration and is carried by rapidly conducting myelinated fibers
fast (delta) pain
slow, poorly localized, aching pain that may follow delta pain and is carried by unmyelinated fibers
slow pain
both the ascending and descending pathways in the spinal cord are located in well defined locations in the _____ matter
white
what are the three types of ascending/descending pathways?
- LONG ASCENDING fibers going to thalamus/cerebellum/brainstem
- LONG DESCENDING fibers going from cerebral cortex/brainstem to spinal cord gray matter
- SHORT PROPRIOSPINAL fibers interconnecting different spinal cord levels (used for reflexes)(will not be taught about)
fibers with similar connections (destinations) tend to travel together and form ____ in the spinal cord
tracts
descending tracts are primarily located in the _____ and _____ funiculi
- anterior (AF)
- lateral (LF)
ascending tracts are found in all three ______
funiculi
anterior, lateral, posterior
propriospinal fibers surround the spinal cord ____ matter
gray
the medial lemniscus system is located in the ____ column and conveys ____ and _____ _____ info
- posterior
- touch
- limb position
column that is comprised mostly of ascending large myelinated primary afferents from various mechanoreceptors
posterior column