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22 Cards in this Set
- Front
- Back
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4 things UMNs are responsible for
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1. Initation of voluntary movement of limbs or skeletal muscles of head
2. Maintenance of normal muscle tone 3. Regulation of posture to provide a stable background on which movement can occur 4. Regulation of many visceral functions |
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Where do you find UMNs in spinal cord?
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Ventral and lateral funiculi
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What are the two divisions of UMN systems?
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Pyramidal and Extrapyrmidal system
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What is the only tract of the pyramidal system we are concerned with?
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Lateral corticospinal tract
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What UMN tract is the key pathway in initating and regulating voluntary motor control? What would you see if it was damaged?
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Rubrospinal tract
*difficulty initiating movement *UMN signs *postural response deficits *profound gait abnormalaties |
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What is the tectospinal tract involved with?
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Initiate turning the head and neck toward or away from sudden visual or auditory stimuli (sight/sound avoidance)
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What does the tectotegmentospinal tract stimulate?
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Via interneurons, it stimulates GVE LMN in the lateral intermediate gray coloumn of T-T4 cord segments which, in turn, dilate the pupils
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What are the three exrapyramidal UMN tracts that arise in the midbrain?
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Rubrospinal tract,Tectospinal tract, and Tectotegmentospinaltract
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What UMN tract is the key pathway in initating and regulating voluntary motor control? What would you see if it was damaged?
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Rubrospinal tract
*difficulty initiating movement *UMN signs *postural response deficits *profound gait abnormalaties |
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The extrapyramidal UMN that arises in the pons?
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Pontine reticulospinal tract
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What is the major UMN tract to control posture and locomotion in animals?
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Pontine reticulospinal tract
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What are the 3 extrapyramidal tracts that arise from the medulla?
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Medullary reticulospinal tract, Lateral vestibulospinal tract, and medial longitudinal fasiculus
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What are the 4 signs or Horner's syndrome?
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1. Ptosis
2. Mitosis (constricted pupil) 3. Enopthalmos (sunken eyeball) 4. Protrusion of 3rd eyelid |
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What difference would you see if a lesion was rostral or caudal to the mesencephalon?
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*Lesions from the CAUDAL mesencephalon cause an observable gait deficit and postural problem on the same side
*Lesions from the ROSTRAL mesencephalon do not cause a gait deficit but cause a postural deficit |
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Where are the 8 UMN tracts located in the brain?
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forebrain-1
midbrain-3 pons-1 medulla-3 |
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Forebrain lesions will cause postural response problems on the opposite side of the lesion-why?
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The lateral corticospinal tract crosses over at the medulla
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What is the main function of the cerebellum?
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It coordinates (smooths and adjusts) all skeletal muscle actions
*Controls rate,range, and force of motion |
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3 layers of the cerebellar cortex
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1. Molecular layer
2. Purkinje layer 3. Granular layer |
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What is the outermost layer of the cerebellar cortex?
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*Molecular layer
*All incoming info must pass through this layer (very sparse neurons) |
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What cells are inhibitory to the cells of the deep cerebellar nuclei?
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purkinje cells
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Which cells excite the purkinje cells?
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granular cells
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What is the only efferent cell of the cerebellar cortex?
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Purkinje cell
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