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14 Cards in this Set
- Front
- Back
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T/F:
Recovery of function in the nervous system is generally due to regeneration of tissue. |
False: recovery of function int the nervous system is rarely associated with regeneration of tissues.
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What are the three basic requirements for successful regeneration of neural tissue?
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1.Replacement of lost neurons
2.Growth of axons 3.Specificity of connections |
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Is the ability to regenerate optic nerve and retinal neurons a selective advantage for frogs?
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No - this is a developmental advantage that allows the frog's eye to grow in proportion to its body.
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What neural cells have been shown to regenerate constitutively in mammals? In what part of the nervous system are these cells found?
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Granule cells found in the olfactory bulb and dentate nucleus of the hippocampal gyrus.
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What effect did being in an enriched environment have on the number of granule cells in the hippocampuses of experimental mice?
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The number of granule cells increased, but this effect was due to decreased turnover rather than increased proliferation.
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How is hippocampal size related to depression? What effect do SSRI's have on this relationship?
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Depression is correlated with smaller hippocampal size. Treatment with SSRI's is correlated with an increase in hippocampal size due to increased granule cell proliferation.
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Describe the results that were obtained when rats with induced PD were treated with stem cell transplants.
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There was some differentiation into dopaminergic cells, with 50% showing alleviation of symptoms. However, 25% developed non-metastasizing tumors.
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What is thought to prevent regeneration of axons in the CNS?
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Oligodendrocytes express compounds (e.g. Nogo-A) that prevent the regrowth.
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What is the normal function of Nogo-A?
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It is expressed by oligodendrocytes during development to prevent aberrant or excessive axonal growth.
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What techniques can improve (but not perfect) axonal growth in the CNS?
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*application of antibodies against Nogo-A
*use of PNS grafts |
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Give an explanation for the success of physical therapy that does not involve undamaged areas "taking over" the function of damaged areas.
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It is possible that the person is simply learning a new task (albeit one with the same goal) that involves different areas of the brain.
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Why might children have better plasticity following a CNS injury and regain more function than adults?
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Because the localization of function in their nervous system has not yet become fixed by experience.
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How is CNS plasticity in children demonstrated with repair of a brachial avulsion?
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An intercostal nerve is inserted into the distal end of the musculocutaneous nerve and eventually is able to provide appropriate innervation to the arm muscles.
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What is meant by "compromised neurons"?
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Neurons in the area surrounding immediate damage that are not killed, but temporarily lose function due to inflammation, edema, and compromised blood flow.
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