Term
| What is the function of oligodendrocytes? |
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Definition
| Myelin producing cells of the CENTRAL nervous system |
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Term
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Definition
| Cells that provide structural support, control the ionic and chemical environment |
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Definition
| Myelin-producing cells of the PERIPHERAL nervous system |
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Term
| What is the function choroid plexus? Where is it located? |
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Definition
| produces and maintains CSF. CP lines the ventricles of the brain. |
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Term
| Your patient is having spastic weakness in her lower extremities. She tells you she's having an "overactive" bladder resulting in incontinence. On exam, she's got 4+ reflexes. Which spinal cord tract is most likely affected? |
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Definition
Corticospinal (pyrimadal tract)
-specifically, this patient's presentation points to an UMN pattern of weakness
[image]
The CST starts with the UMN in the cerebral cortex which descends through the corticospinal tracts in the spinal cord. It crosses and synapses with the LMN in the spinal cord, and the LMN then traverses directly to somatic skeletal muscles. Lesions produce different signs and symptoms depending on whether the UMN or LMN is affected.
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Term
Your patient, Al, is having flaccid paresis of his arms. His muscles show signs of wasting and you can't elicit any reflexes on neurologic exam. You notice tiny fasciculations in the muscle.
Is he suffering from an UMN or LMN pathology? |
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Definition
Al has a LMN lesion. Review and understand this chart.
| Lower motor neuron weakness (LMN) |
Upper motor neuron weakness (UMN) |
| Flaccid |
Spasticity |
| Decreased tone |
Increased tone |
| Decreased muscle stretch reflexes |
Increased muscle stretch reflexes |
| Profound muscle atrophy |
Minimal muscle atrophy |
| Fasciculations present |
Fasciculations absent |
| May have sensory disturbances |
May have associated sensory disturbances |
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Term
| Your patient is complaining of "numbness" in her R lower extremity. On exam, you notice that she has reduced sensation to vibration, light touch, and proprioception in the R leg. She has intact sensation to painful simuli. Which spinal cord tract is likely affected? |
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Definition
Her right dorsal column-medial lemnicus tract has been lesioned. Make sure you understand why spinal cord lesions to the DCML tract produce ipsilateral lesions.
Brief explanation:
DCML originates in peripheral sensory nerves, ascends ipsilaterally thru the spinal cord, crosses in the medulla and then projects contralaterally to the cortex.
More involved Review of tract anatomy:
Large diameter fiber sensory input on proprioception, light touch, and movement enter the dorsal nerve roots and ascend IPSILATERALLY via the DCML system to the medulla. In the medulla, the axons synapse on the ipsilateral dorsal column nuclei, then decussate, sending their axons through the medial lemnicus in the brainstem. After, this synapse, fibers ascend CONTRALATERALLY through the pons, midbrain, and then finally to the primary sensory cortex.
[image] |
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Term
| Your patient Rodrigo stepped into scalding hot bath water this morning. He withdrew his right leg immediatley because of the intense pain. He noticed no such sensation in the left leg. If the lesion occurs in the spinal cord, which tract is likely affected? |
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Definition
Rodrigo likely has a lesion of his left spinothalamic tract.
Short and sweet:
Ipsilateral pain and temp fibers from the body enter the spinal cord, and cross almost immediately in the spinal cord; they then ascend contralaterally where they synapse in the thalamus and continue to project contralaterally to the cortex.
A little longer:
Small diameter fiber sensory input about pain and temperature enters the dorsal nerve root, ascends ipsilaterally a few levels, crosses the midline and ascends in the lateral colums, through the contralateral medulla, through the contralateral pons, though the midbrain, to the contralateral ventral thalamus to synapse there. The second order axons then project to the primary sensory cortex.
[image]
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Term
| What is the function of the cerebellar vermis? |
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Definition
The vermis:
-receivesinfo about proprioception from the spinocerebellar tract |
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Term
| What is the function of the cerebellar hemispheres? |
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Definition
| modulate voluntary movement of the extremities |
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Term
| Dysdiadkinesia, intention tremor, nystagmus, ataxia are signs that a patient may have dysfunction in their _____________. What carries blood to this structure? |
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Definition
| Cerebellum. The cerebellum receives blood from the vertebrobasilar system. |
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Term
Your patient is stabbed in the back and has had full hemisection of the spinal cord at T10 affecting the left side of his spinal cord (Brown-Sequard lesion). Predict his deficits.
[image] |
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Definition
A true test of how comfortable you are with the tracts.
Deficits:
1. Loss of light touch/proprioception (DCML) on the LEFT below the lesion
2. Loss of pain and temperature sensation on the RIGHT below about T12-L1(remember Spinothal tract fibers ascend a couple of levels before decussating)
3. UMN, spastic paresis on the LEFT side; LMN, flaccid paralysis at the level of the lesion |
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Term
| Which brainstem structure contains the nuclei for CN III-IV |
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Definition
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Term
| Which brainstem structure contains the nuclei for CNs V-VIII? |
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Definition
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Term
| Which brainstem structure contains the nuclei for CNs IX-XII? |
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Definition
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Definition
kinda fun:
http://www.wisc-online.com/Objects/ViewObject.aspx?ID=AP11504 |
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Term
| What is the typical pattern of deficits for lesions orginating in the brainstem? |
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Definition
| Lesions in the brainstem will produce CROSSED findings: ipsilateral cranial nerve deficits and contralateral somatic deficits |
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Term
| You have a patient with rigidity, slowness of movement, resting tremor, and chorea. Which structure of the brain is likely affected? |
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Definition
| The basal ganglia. Receives it's blood supply from deep penetrating branches of the ACA and MCA. |
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