MODULE 9- Upper Motor Neuron Control of the Brain + Spinal Cord Flashcards
(36 cards)
lower motor neurons
the “final common path” for initiating movement
descending systems (upper motor neurons)
-motor cortex
-brainstem centers
motor cortex is responsible for
planning, initiating, + directing voluntary movements
brainstem cortex is responsible for
stereotypical movements, postural control, + gain adjustments
basal ganglia is responsible for
initiation of intended movement + suppression of unwanted movement
cerebellum is responsible for
coordination of ongoing movement
local circuit neurons are responsible for
sensorimotor integration + central pattern generation
motor neuron pools consist of
lower motor neurons
motor + “premotor” areas of the FRONTAL LOBES are important for what
planning + precise control of movement
lateral/ventral corticospinal tract
limb/trunk muscles
corticobulbar tract
facial muscles + tongue
motor control centers in the BRAINSTEM are important for
postural control
motor control centers of frontal lobes (2)
-lateral/ventral corticospinal tract
-corticobulbar tract
motor control centersof brainstem (2)
-lateral + medial vestibulospinal stracts
-reticulospinal tract
upper motor neurons in cerebral cortex to lower motor neurons in medial ventral horn is direct/indirect
indirect
upper motor neurons in cerebral cortex to lower motor neurons in lateral ventral horn are direct/indirect
direct
premotor cortex or primary motor cortex is more anterior
premotor cortex
premotor cortex does movement planning/execution
movement planning
primary motor cortex does movement planning/execution
movement execution
what are the upper motor neurons of the primary motor cortex
pyramidal cells of cortical layer 5
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Betz cells
largest neurons in the human CNS
-accounts for 5% of the corticospinal tract
what accounts for the rest of the upper motor nuerons in the primary motor cortex + premotor cortex
smaller non-Betz cells
are Betz cells the principal upper motor neurons of the motor cortex
NO
-Betz cells are often wrongly assumed to be the principal upper motor neurons of the motor cortex
-pyramidal cells of cortical layer 5 are
despite their small numbers, Betz cells play an important role in what
the activation of lower motor neurons that control muscle activities in the distal extremities