Motor Tracts 2 Flashcards
(21 cards)
What are the 3 major subareas of the motor cortex?
Primary motor cortex, Premotor area, Supplementary motor area.
What is the function of the primary motor cortex (Area 4)?
Controls voluntary movement, especially fine motor skills of hands and speech; initiates specific movements.
What is the role of the premotor area?
Plans and organizes complex movements; forms a motor image before execution.
What does the supplementary motor area do?
Coordinates bilateral movements and postural adjustments, supports motor control by other motor areas.
What happens if Broca’s area is damaged?
The patient can vocalize sounds but cannot speak full words—limited to basic expressions like “yes” or “no”
What is motor apraxia?
A condition where hand movements become uncoordinated and purposeless due to lesion in hand skills area.
Where do corticospinal tract fibers originate?
30% from primary motor cortex, 30% from premotor/supplementary areas, 40% from somatosensory cortex.
What are Betz cells?
Large pyramidal neurons in the primary motor cortex responsible for rapid motor signals.
What happens to corticospinal fibers at the medulla?
Most decussate (cross over) to form the lateral corticospinal tract; a few remain uncrossed (ventral tract).
What is the corticorubrospinal pathway?
An accessory route for motor signals via the red nucleus; mainly for small muscle group control.
What tracts are part of the extrapyramidal system?
Reticulospinal, vestibulospinal, rubrospinal, and cerebellar pathways via basal ganglia, red nucleus, etc.
What is the role of the brainstem in motor control?
Regulates breathing, cardiovascular function, GI activity, posture, equilibrium, and eye movements.
What does the pontine reticulospinal tract do?
Excites axial and extensor muscles for posture and antigravity support.
What is the function of the vestibulospinal tract?
Maintains equilibrium and activates antigravity muscles based on input from the vestibular system.
Which motor cortex region is primarily responsible for forming a “motor image” of complex movement patterns?A. Primary motor cortexB. Supplementary motor areaC. Premotor areaD. Broca’s area
C. Premotor area
Which of the following best describes the function of Betz cells?A. Carry auditory signals to the brainstemB. Process visual informationC. Generate high-velocity motor commandsD. Inhibit motor neuron activation
C. Generate high-velocity motor commands
A lesion in which area causes motor apraxia?A. Broca’s areaB. Primary motor cortexC. Premotor hand skills regionD. Supplementary motor cortex
C. Premotor hand skills region
Which structure do corticospinal tract fibers pass through before reaching the spinal cord?A. Corpus callosumB. Anterior hornC. Internal capsuleD. Cerebellar peduncles
C. Internal capsule
Which of the following tracts crosses at the level of the red nucleus and helps control distal muscles?A. Rubrospinal tractB. Vestibulospinal tractC. Pontocerebellar tractD. Ventral corticospinal tract
A. Rubrospinal tract
What is the primary function of the pontine reticulospinal tract?A. Inhibits antigravity musclesB. Excites axial and extensor musclesC. Controls facial expressionD. Coordinates voluntary breathing
B. Excites axial and extensor muscles
A patient suffers a lateral medullary infarct. Which of the following symptoms is least expected?A. Contralateral body numbnessB. Ipsilateral facial sensation lossC. UnconsciousnessD. Ataxia and dizziness
C. Unconsciousness
