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26 Cards in this Set
- Front
- Back
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what do the propriospinal axons form for the spinal cord?
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local circuitry
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what are long tracts?
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tracts that carry information between the spinal cord and cerebrum or brainstem
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what are the 5 primary spinal cord long tracts?
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corticospinal tract, posterior (dorsal) column-medial lemniscal system, anterolateral system, spinocerebellar, and hypothalamospinal system.
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what is the corticospinal tract responsible for?
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volitional motor
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what is the dorsal column-medial lemniscal system responsible for?
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discriminative touch (epicritic), vibration sense and proprioception
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what is the anterolateral system responsible for?
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pain, temperature, crude (protopathic) touch
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what are the spinocerebellar tracts responsible for?
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unconscious proprioception, information from muscle (spindles and golgi tendon) conveyed to cerebellum
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what is the hypothalamospinal system responsible for?
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central control of preganglionic autonomic neurons in the spinal cord.
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what system is the major source of volitional motor control in humans?
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pyramidal
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where are the neurons of origin in the pyramidal system?
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cerebral cortex (esp primary motor cortex and related areas in frontal lobe, some sensory too)
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what are the two locations that the pyramidal system sends fibers to from the cererbral cortex?
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brainstem and spinal cord
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what are the two primary types of neurons that control motor via the corticospinal tract?
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those in the motor cortex of the brain and motor neurons in the spinal cord
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which neurons are called upper motor neurons? which neurons are called lower motor neurons?
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upper- cortical neurons of the pyramidal tract and lower- spinal cord and brainstem motor neurons that directly innervate muscle.
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where is the origin and termination of the upper motor neurons? how does this differ from the origin and termination of the lower motor neurons?
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upper- origin and termination is within the CNS
lower- originate in CNS but terminate in the periphery |
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what system is the corticospinal tract a part of?
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the pyramidal
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what is the major descending motor pathway?
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cortiocospinal tract
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where do 2/3s of the axons of the corticospinal tract originate from? where does the other 1/3 originate from?
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neurons in motor cortex (frontal cortex and precentral gyrus); sensory areas (primary sensory cortex and parietal areas)
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where do 80-90% of the pyramidal axons cross at? where does it descend into?
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midline at the level of the foramen magnum; descends in the dorsal part of the lateral funiculus on the contralateral side.
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if a patient came in with a stab wound in lateral fasciculus at C7, on what side of the body would you expect the deficit to be? what will the deficit be?
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ipsilateral because the lateral corticospinal tract (which is in charge of motor) crosses over at the level of the medulla. So if the lesion is below the medulla then the affect will happen on the same side.
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what percentage of pyramidal axons do not cross? what do they form?
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10-20% forming the anterior corticospinal tract
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where does the anterior corticospinal tract descend in?
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spinal cord in the anterior funiculus
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what will cross the midline at the spinal level at which they innervate motor neurons and interneurons?
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the axons from the anterior corticopinal tract will form collaterals which will do the crossing.
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which tract primarily innervates axial musculature?
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anterior corticospinal tract
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how are most motor neuron pools of the corticospinal tract innervated?
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via interneurons; some alpha motor neurons directly, but not a lot
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corticospinal axons are _____ to extensors and _______ to flexors.
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inhibitory; excitatory
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what is the primary function of the corticospinal tract?
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control of fine skilled movements in the extremities
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