Basic Sensory/Motor tracts Flashcards
What type of reflex is involved in the jaw-jerk and patellar reflexes?
Myotatic reflex (monosynaptic)
Main features of a secondary neuron in a conscious sensory pathway?
Decussates, and ascends as a lemniscus -> terminates on tertiary neuron in dorsal thalamus
LMNs originate where in the spinal cord?
Anterior horn cells
UMNs forms what tract after they decussate?
Lateral Corticospinal tract (decussate at pyramids)-> terminate in LMN pols
What are the posterior columns responsible for?
Proprioception and 2-point tactile discrimination
The dorsal column/medial lemniscal system carries what kind of information?
Proprioception, 2-point tactile discrimination, vibratory and pressure sensations
What carries proprioceptive/2-pt tactile input to UE, and LE, respectively?
fasciculus cuneatus and fasciculus gracilis
What type of lesion causes a positive Babinski sign?
UMN lesion
What pathway is responsible for fast pain?
Lateral Spinothalamic tract- Sharp, localized pain/temp sensation
Contralateral loss of pain/temp sensation 2 sensory dermatomes below lesion indicates what?
Lateral spinothalamic tract lesion
Brown-Sequard syndrome is what? Sx?
Hemisection of spinal cord. Results in ipsilateral loss of proprioception/2-pt tactile (posterior columns), ipsilateral spastic paralysis (motor tracts) and contralateral loss of pain/temp sensation 2 sensory dermatomes below lesion (LSTT)
Destruction of the anterior white commissure results in what?
B/L loss of pain/temp sensation to UE (yolk-like anesthesia)
What makes up the spinal lemniscus?
VSTT (crude tactile) and LSTT (Fast pain/temp)
Where do the superior sagittal venous sinus and straight sinuses drain into?
Superior sagittal-> R transverse sinus
Straight sinus-> L transverse sinus
What cranial nerves are responsible for taste?
Anterior 2/3= CN5
Posterior 1/3= CN9
All U/L lesions of the lateral spinothalamic tract result in what?
Contralateral loss of pain/temp 1-2 segments below lesion
What would a U/L lesion of the Spinal lemniscus result in?
Contralateral loss of pain/temp from the body
What would a U/L lesion of the medial lemniscus result in?
Contralateral loss of proprioception/2-point tactile discrimination from the body. (remember- lemniscus is in brainstem)
Where does the corticospinal tract decussate?
At the pyramids (contralateral hemiplegia if injured above them)
Where does the spinothalamic tract decussate?
Anterior white commissure (Injury always contralateral loss of pain/temp)
