Tract generalities Flashcards
What is the primary job of the posterior column-medial lemniscus system?
Convey touch, pressure, vibration, joint position/movement
Does the posterior column-medial lemniscus system cross the midline? If so where?
crosses midline at the level of the caudal medulla where the internal arcuate fibers form the medial lemniscus
Where are all of the cell bodies of the posterior column medial lemniscus system located?
they are located in DRG on the ipsilateral side on the level to which they entered the spinal cord
Where do the third order fibers originate in the posterior column medial lemniscus system? and where do they end up?
originate in the thalamus (ventral posterolateral nucleus) and ascend through the internal capsule and synapse in the primary somatosensory cortex (post central gyrus)
What can injury to the posterior column medial lemniscus system result in?
- impaired proprioception and discriminative tactile functions (esp complex tactile discrimination)
- proprioception can also be lost completely resulting in ataxia
What is the primary responsibility of the spinothalamic tract/anterolateral pathway?
responsible for conscious awareness of pain, temp, and some mechanoreceptors
Where do most of the fibers in the spinothalamic/anterolateral pathway synapse?
substantia gelatinosa in laminae II
Do the fibers in the spinothalamic pathway cross the midline? If so where?
Neurons in this pathway cross the midline with ROSTRAL inclination in the anterior commissure of the spinal cord
What is they relay point for the spinothalamic/anterolateral pathway?
Ventral psoterolateral nucleus (mostly) with some in other thalamic nuclei
What is the result of a lesion to the spinothalamic/anterolateral pathway?
contralateral (opposite side) anagesia and loss of temp sensation
What are the types of fibers that make up the anterolateral pathway?
spinothalamic, spinoreticular, spinomesencephalic
