SOMATIC MOTOR SYSTEM Flashcards
SUPERIOR COLLICULUS
receives axons from optic tract + projects to contralateral spinal cord via tectospinal tract
contributes to control of head + eye movements in response to visual input
1ST ORDER NEURON
impulse from receptor to CNS
2ND ORDER NEURON
impulse from CNS to thalamus
3RD ORDER NEURON
impulse from thalamus to primary somatosensory cortex
EXTRAPYRAMIDAL (INDIRECT) TRACTS
- rubrospinal
- tectospinal
- vestibulospinal
PYRAMIDAL (DIRECT) TRACTS
- lateral corticospinal
- anterior corticospinal
- corticobulbar
RUBROSPINAL TRACT
input to tone + posture
originates in red nucleus
TECTOSPINAL TRACT
impulses to control movement of head in response to visual stimuli
originated in superior colliculus
VESTIBULOSPINAL TRACT
impulses that regulate muscle tone in response to head movements - equilibrium
originated in vestibular nucleus of medulla
LATERAL CORTICOSPINAL TRACT
upper motor neurons CROSS in medulla
lower motor neurons exit all levels of spinal cord
lower motor neurons terminate in skeletal muscles
ANTERIOR CORTICOSPINAL TRACT
upper motor neurons DON’T CROSS in medulla
lower motor neurons control muscles of neck + part of trunk
CORTICOBULBAR TRACT
upper motor neurons CROSS + terminate in nuclei of cranial nerves
conveys impulses that control voluntary movements of head + neck
UPPER MOTOR NEURON
carries impulse from cerebral cortex to cranial nerve nuclei or spinal cord
LOWER MOTOR NEURON
terminates in skeletal muscles
extends from CNS to muscle
SPINOTHALAMIC TRACTS
from skin to thalamus
posterior - discriminative touch, proprioceptors + vibration
anterior - light touch + pressure
lateral - pain + temperature
