pyramidal motor system
Học thuậtThân thiện
A doctor points to a diagram of the pyramidal motor system on a medical chart.
Definition
- Noun:
- A major descending motor pathway: The pyramidal motor system refers to a collection of critical nerve tracts that originate in specific brain regions, travel through the brainstem, and connect directly to motor neurons controlling voluntary muscle movement.
- The primary pathway for voluntary movement: It is the principal neural system responsible for initiating and controlling precise, voluntary movements of the body, particularly fine motor skills.
Usage Examples
- Noun:
- Damage to the pyramidal motor system can result in paralysis or significant weakness on the opposite side of the body.
- The neurologist tested the patient's reflexes to assess the integrity of the pyramidal motor system.
- Signals from the brain's motor cortex travel down the pyramidal motor system to execute a command like moving a finger.
Advanced Usage
- "Pyramidal tract": Often used synonymously with the corticospinal tract, which is the largest component of the pyramidal motor system.
- The lesion was found in the pyramidal tract within the medulla.
- "Pyramidal signs": Clinical indicators, such as hyperreflexia or the Babinski sign, that suggest dysfunction within this system.
- The presence of pyramidal signs pointed to an upper motor neuron lesion.
Variants and Related Words
- Corticospinal tract (n): The major pathway within the pyramidal system that descends from the cortex to the spinal cord.
- Corticobulbar tract (n): The component of the pyramidal system that terminates in the brainstem (bulb) to control cranial nerve nuclei.
- Upper motor neuron (n): A neuron whose cell body is in the cerebral cortex and whose axon forms part of a pyramidal tract.
Synonyms
- Corticofugal pathways: A more general term for neural pathways that carry signals away from the cerebral cortex.
- Descending motor pathways: A broad category that includes the pyramidal system and other tracts like the extrapyramidal system.
Related Phrases
- Pyramidal decussation: The crossing-over point of most pyramidal tract fibers in the lower medulla oblongata.
- At the pyramidal decussation, the axons cross to the contralateral side of the spinal cord.
- Pyramidal system lesion: Damage to this specific neural pathway.
- A stroke commonly causes a pyramidal system lesion, leading to hemiparesis.
A doctor points to a diagram of the pyramidal motor system on a medical chart.
Noun
- any of the important motor nerves on each side of the central nervous system that run from the sensorimotor areas of the cortex through the brainstem to motor neurons of the cranial nerve nuclei and the ventral root of the spinal cord