Midterm 2 Flashcards
(294 cards)
What does the anterolateral system transmit?
nociceptive, itch, thermal, and crude touch info
What is the sequence of neurons in the anterolateral system?
1st order neuron in DRG, 2nd order neuron in dorsal horn, 3rd order neuron in thalamus
also could include interneurons
What is the direct pathway of anterlateral system?
spinothalamic tract/neospinothalamic
the 2nd order neuron in this case synapses w/contralateral thalamus and sends collaterals to reticular formation
What is the indirect pathway of anterolateral system?
spinoreticular tract
indirect b/c 2nd order neuron goes to retucular formation before sending collaterals to thalamus
What are the differnt tracts in anterolateral system? (6)
spinothalamic, spinoreticular, spinomesencephalic, spinotectal, spinohypothalmic, spinobulbar
What is Brown-Sequard syndrome? (cause)
incomplete injury to spinal cord (hemisected), ascending and descending tracts on that side are damaged
What are the symptoms of Brown-Sequard syndrome?
weakness or paralysis, proprioceptive deficits, two point discrimination, fine touch, astereognosis on the side of the body ipsilateral to the lesion, and loss of pain and temperature sensation on the contralateral side
What is astereognosis?
unable to identify shape of known object when eyes are closed and touching it
What is congential insensitivity to pain (CIP)?
rare (1 in 125 million), lack of pain sensitivity, likely due to mutations that stop nociceptors in the dorsal root ganglion from sending signals
What are contact receptors?
type of exteroreceptor
transmit tactile, pressure, pain, or thermal stimuli (requires touching)
What does the dorsal column-medial lemniscal system (DCMLS) relay?
fine tactile sense, flutter-vibratory sense, proprioception
What is dorsolateral fasiculus?
fibers split into direct and indirect pathways of ALS, made up of thinly myelinated and unmyelinated axons
aka tract of lissauer
What are some examples of encapsulated mechanoreceptors?
meissner’s corpuscles, pacinian corpuscles, ruffini’s organs
What determines if mechanoreceptors is encapsulated or nonencapsulated?
depends on whetehr a structural device encloses it peripheral nerve ending
What are examples of nonencapsulated mechanoreceptors?
free nerve endings, merkel’s tactile discs, peritrichial nerve endings
What are exteroceptors?
close to body surface and detect sensory info from environment
sensitive to touch, pressure, temperatrue, pain, and flutter vvibration
What are the two types of exteroceptors?
teloreceptors and contact receptors
What is the fasciculus gracilis?
tract in the DCMLS, transmits info from the mid-thoracic level and below, including the lower limbs
What is the fasciculus cuneatus?
transmit the info from the upper extremities (sparing the head
tract in DCMLS
What do free nerve endings respond to?
touch, pressure
What does the General Somatic Afferent system transmit?
SENSORY info like touch, pressure, flutter-vibration, pain, temp, itch, stretch, position from SOMATIC structures
What does the General Visceral Afferent system transmit?
SENSORY info like touch, pressure, flutter-vibration, pain, temp, itch, stretch, position from VISCERAL structures
What are interoreceptors?
detect sensory info concerning body’s internal environment
Blood pressure, pH, oxygenation, osmolarity
What do mechanoceptors detect?
touch, pressure, two point discrimination, vibration, stretching, hair movement