Motor Systems Flashcards
What are the two major motor systems?
- Pyramidal (cortex to motor effector, brainstem)
- Extrapyramidal (helps modulate, basal ganglia and cerebellum)
What are the two major pyramidal systems?
1-corticobulbar
2-corticospinal
Where do reflexes take place?
spinal cord
Where do stereotyped, repetetive movements take place?
- spinal cord
- brainstem
- cerebellum
Where do goal-directed, voluntary movements take place?
- cortex
- basal ganglia
How many neurons are in the Pyramidal system?
2 neurons
What two things does the stretch reflex detect?
- length
- rate of change
What are the two ways to excited a muscle spindle?
1-muscle stretch (relaxes muscle and contracts antagonist)
2-Gamma fiber signal (voluntary contraction or loading muscle)
What are the three major limbs/sections of the Internal Capsule?
1-Anterior limb (not clinically relevant)
2-Genu (knee or bending portion, cotricobulbar/face)
3-Posterior limb (Costicospinal/motor)
Roughly ____% of the pyramidal system decussates at the medulla. _______% stars ipsilateral (___% anterior and ______% lateral)
90, 10, 8, 2
Cranial nerve nuclei are part of which system?
Corticobulbar tract in the genu of the internal capsule
Which two nuclei are exceptions to being bilateral in the Corticobulbar tract?
- Facial nerve from the eye down
- Hypoglossal nerve
*both are contralateral
What are 5 signs of upper motor neurons (betz cells/cerebral cortex)?
1-weakness of entire limb 2-Spasticity of affected muscle 3-no muscle atrophy 4-Hyperactive deep tendon reflex 5-Pathologic reflexes, babinski
What are 5 signs of lower motor neurons (brainstem or spinal cord)?
1-Weakness in discrete muscle area 2-flaccidity of affected muscle 3-prominent muscle atrophy 4-hypoactive deel tendon reflex 5-no pathologic reflex
The extrapyramidal tract dealing with support posture, balance and head movements is called what?
Vestibulospinal tract
*relays information from the vestibular nuclei
Which extrapyramidal tract deals with reflex postural movements of head and visual input?
Tectospinal tract (originates in midbrain tectum/superior colliculus)
Which extrapyramidal tract originates in the red nucleus and performs planned movements?
Rubrospinal tract
*axons decussate in midbrain
The striatum is made up of what?
Caudate and Putamen
The lenticular nuclei is made up of what?
Putamen and globus pallidus
The ventral palladium is made up of what?
base of caudate head and ventral putamen (limbic)
What are the two regions of substantial nigra?
1-pars compacta (black due to neuromelanin)
2-pars reticulata (greyish, GABAergic, output of BG)
What two things give input to the Basal Ganglia circuitry?
1-Caudate
2-putamen
What two things are output for the Basal Ganglia circuitry?
1-Globus pallidus (internal segment)
2-Substantia nigra (pars reticulata)
What two things are intrinsic for the BG Circuitry?
1-globus pallidus (external segment)
2-Subthalmic nucleus
What acts as a modulatory aspect of the BG circuitry?
Substantia nigra (pars compacta)
What promotes movement?
Dishinhibition of thalamocortical circuits
What does the direct pathway do?
facilitates movement
what does the indirect pathway do?
inhibits movement
What is hyperkinesia?
excessive movements such as in huntingtons disease
What is hypokinesia?
Decreased movement such as in parkinsons disease
Involuntary quick jerky movements are called what?
Chorea
Repetetive large amplitude involuntary movements are called what?
Hemiballism
What is the anatomical sign of huntingtons?
striatal atrophy
Slowness to execute a movement is called what?
bradykinesia
involuntary tremor type movement is called what?
Dyskinesia
Inability to initiate movement is called what?
Akinesia
What is anatomically observed in parkinsons?
loss of substantia nigra
In parkinson disease _______ pathway is less active while the __________ pathway is more active
Direct, indirect
The modulation of ipsilateral intentional movements happens where?
Cerebellum
What are the 6 landmarks of the cerebellum from a lateral view?
1-Anterior lobe 2-Primary Fissure 3-Posterior lobe 4-Tonsil 5-Flocculus 6-Middle cerebellar peduncle
The ________ separates left and right cerebellar lobes
Vermis
What is found where the two Flocculi come together that helps work with gate?
Nodulus
What are the 3 cell layers of the small folia of the cerebellum?
- Outer: stellate and basket cells
- Middle: parking cells
- inner: Granule and golgi cells
What two fibers are afferents?
climbing(end on purkinje) and mossy fibers (end on granule cells)
What cells are responsible for efferents?
purkinje cells (go to cerebellar nuclei or vestibular nuclei
What are the 4 nuclei of the cerebellum?
1- Fastigial nucleus (vestibular)
2- Globose nucleus (muscle tone)
3- Emboliform nucleus (muscle tone)
4- Dentate nucleus (Coordinate, fine voluntary motor activity)
What are the 3 divisions of the peduncles?
1-Superior (SCP): Midbrain (efferents to thalamus)
2-Middle (MCP): Pons (corticopontocerebellar afferents)
3-Inferior (ICP): Medulla (spinocerebellar afferents and efferents to brainstem)
A lesion in a dorsal nucleus, spinocerebellar tract or ICP would cause cerebellar signs on which side?
Ipsilateral side
What does a spinocerebellar ataxia affect?
- Walking/balance gait problems
- Loss of precision and timing of movement
- Swallowing
- depth perception
A large cerebellum or a small foramen magnum can result in what?
Chiari malformation
Degeneration of the anterior cerebellar lobe that affects Gait, trunk and lower limb ataxia is called what?
alcoholic cerebellar degeneration
