Nerve Tracts/Pathways Flashcards
Thalamus
-interprets sensation information and perceives it
Name of Pathways
-origin and site of termination for 2nd order neruon
Types of Somatosensory Pathways to Brain
Conscious Relay:
-info about location and stimulus type to conscious awareness
-discriminative sensations
Divergent:
-info to many locations in brainstem and cerebrum
-conscious and non-conscious
Non-Conscious Relay:
-proprioceptive and other movement to cerebellum
Conscious Relay Pathways
-info about location and stimulus type to conscious awareness
-discriminative sensations
Crude Awareness: thalamus
Detailed Awareness: somatosensory cortex
Dorsal Column
Anterolateral Column
Divergent Relay Pathways
-info to many locations in brainstem and cerebrum
-conscious and non-conscious
-medial/slow nociception
-subconscious temperatue
Spinomesencephalic, spinoreticular and spino-emotional tracts
Non-Conscious Relay Pathways
-proprioceptive and other movement to cerebellum
Spinocerebellar Tracts
Grey Matter Fibers
-Motor
-cortex filled with cell bodies, folded in 6 layers
-Pyramidal cell: primary output
White Matter Fibers
Projection fibers, commissural fibers, Association fibers
Descending Motor Fibers
Pyramidal Tracts: cerebral cortex
Extrapyramidal Tracts: Brainstem
Flexor-Extensor Rule
-MNs that innervate flexors are located posteriorly to MNs that innervate extensors
Proximal-Distal Rule
-MNs that innervate distal muscles are located laterally to MNs that innervate proximal muscles
Lateral Corticospinal Tracts
-crossed at pyramidal decussation of medulla
-fractionated movements
-primary motor cortex
-most CST fibers
-descends in lat funiculus
Medial Corticospinal Tracts
-uncrossed
-postural movements
-originates from premotor cortex
-descends in venttral funiculus
Nonspecific Motor tracts
-facilitate activity of interneurons and MNs
-activate during intense emotions
Ceruleospinal and Raphespinal Tracts
Corticobrainstem Tracts
-voluntary control of many MM of head and neck
-originate in cortex motor areas and reach CN nuclei in brainstem