DC-ML N20 Flashcards
DC-ML recognizes
FINE touch, 2-point discrimination, conscious proprioception, and vibration sensations
DC-ML is epicritic or protopathic
EPICRITIC (highly localized and discriminative sensations)
Primary Neuron
cell body = DRG, pseudounipolar neuron with peripheral (distal) and central ( proximal) axonal processes
Receptors associated with DC-ML
Meissner's Corpuscle (A-beta): FINE touch, 2-point Free Nerve Endings on hair follicles (A-beta): FINE touch Pacinian Corpuscles (A-beta): pressure and vibration Muscle Spindles (Ia and II) Golgi tendon organs (Ib)
Peripheral axons of DC-ML
periphery to DRG; large, heavily myelinated (Ia, Ib, II (A-beta))
Central axons of DC-ML
Cell body in DRG through MEDIAL dorsal root entry to fasciculus gracilis/cuneatus to nucleus; large, heavily myelinated
Central axons of DC-ML collateral branches
terminate in gray matter to facilitate spinal reflexes
Fasciculus Gracilis
All levels, lower body sensory, terminates in nucleus gracilis
Level of Nucleus Gracilis?
Caudal medulla
Fasciculus Cuneatus
T6 and ABOVE, sensory from upper body, terminates in nucleus cuneatus
Level of Nucleus Cuneatus?
Caudal Medulla
Somatotopy of DC-ML
more lateral portions of the DC-ML come from the upper body sensory nerves, because each level adds nerves from the outside (sacral spinal levels are medial and cervical spinal levels are lateral)
Primary neuron of DC-ML
psuedounipolar; periphery–>DRG–> dorsal horn–> dorsal funiculus–> nucleus gracilis/cuneatus (level of caudal medulla)
Secondary neuron of DC-ML
Cell body in nucleus of gracilis/cuneatus –> internal arcuate fibers (decussate ventromedially through the medullary tegmentum) –> Medial Lemniscus (Ventral:leg, dorsal:arm) –> terminates in the thalamus
Third order neuron of DC-ML
Cell body located in the Ventral Posterolateral nucleus of the thalamus–> posterior limb of internal capsule –> somatosensory cortex
