Pathology 3500 Chapter Notes - Chapter 2: Upper Motor Neuron, Optic Chiasm, Paraplegia
28 Mar 2020
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Neural progenitors persist in mammalian brain w/capacity to give rise to new neurons. Sectioning the axon of a neuron has dramatically different consequences in the cns/pns: both cases, distal segment degenerates, since it cannot survive without the continuous transport of substances manufactured in the soma. Pns: the proximal stump gives rise to sprouts that are able to grow along the pre- existing structures (schwann cells) and re-establish function. Requirement is the apposition of the proximal and distal stump. In contrast, axonal regeneration is impeded in the cns. Hemiplegia (vs hemiparesis): paralysis (vs weakness) of one side of the body (commonly from a contralateral brain injury) Paraplegia (vs paraparesis): paralysis (vs weakness) of the legs, most commonly due to lesions in the spinal cord. Abnormal sensation: loss of sensation may come in a variety of forms. Paraesthesia (pins and needles): loss of position sense or two point discrimination, loss of pain and temperature sensation.
