Motor Tracts Flashcards
Commands distributed by somatic nervous system (SNS)
Directly contacts from skeletal muscles
Autonomic nervous system (ANS)
- organs
- innervated visceral effectors
- examples: smooth muscles, cardiac muscles, and glands
Upper motor neuron
- deliver motor commands to motor nuclei in brain stem or spinal cord.
- exits cerebral cortex > to brain stem > to spinal cord
- upper motor neuron can excite or inhibit the lower motor neuron
- starts at thalamus > ends at cerebral cortex
Lower motor neuron
- relays motor commands from the CNS motor nuclei to skeletal fibers
- starts at cerebral cortex > ends at spinal cord
info
85% information goes through spinal cord shifts and crosses over
15% information comes straight down
Motor homunculus
Body parts with the most motor activity
Example : hands, tongue
Descending motor tracts Carrying subconscious (automatically) motor commands
1) rubrospinal tract
2) reticulospinal tract
3) tectospinal tract
4) vestibulospinal tract
Descending motor tracts
Carrying conscious motor commands
1) anterior corticospinal
2) lateral corticospinal
Autonomic nervous system tracts
- starts lower level of hypothalamus
- base of brain, brain stem, and spinal cord
- affects organs, smooth muscles, and glands
Somatic motor control functions
- basal nuclei- modify voluntary and reflexive motor patterns at subconscious level
- hypothalamus- controls motor patterns. Eating, drinking, sexual activities
- pons and medulla oblongata- controls balance reflexes, respiratory reflexes.
Planning stage
• when a conscious decision is made to perform a specific movement, information is relayed from the frontal lobe.
Frontal lobe > motor association areas > basal nuclei > cerebellum > exits spinal cord
CNS issues motor commands in response to information provided by
Sensory systems
