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FA-2016 neuro pg 453
firstaid neuro page 453( based of FA 2016)
Question | Answer |
---|---|
what are the signal transmitting cells of nervous system? | neurons |
how often do neurons divide? | permanent cells - do not divide in adulthood |
what are neurons? | signal relating cells with dendrites(receive input), cell body and axon(sends output) |
what do dendrites do? | receive input |
what do axons do? | sends output |
cell body and dendrite can be stained how? | stained via nissl substance (stains RER) |
why axons not stained? | no RER in the axon |
what happens if axon is injured? | it undergoes wallerian degeneration |
what is wallerian degeneration? | degeneration distal to injury and axonal retraction proximally |
what is the work of wallerian degeneration? | allows for potential regeneration of axon(if in PNS) |
function of axon? | physical Support, Repair, K+ metabolism, removal of excess neurotransmitter, component of BBB, glycogen fuel reserve buffer ( SRK is BG Removing excess neurotransmitter) |
how do astrocyte respond to neural injury? | by Reactive gliosis |
what is the marker for astocyte? | GFAP |
astrocyte is derived from what? | neuroectoderm |
what is microglia? | phagocytic scavenger cell of the neruvous system (mesodermal, mononuclear origin) |
germ layer origin of microglia? | mesoderm |
how do microglia stain with nissl stain? | not readily discernible with nissl stain |
what happens to microglia in HIV? | HIV inected microglia fuse to form giant cell in the CNS |
what is the function of myelin? | wraps and insulates axons : 1) increase space constant 2) increase conduction velocity |
fuction (particularly increase condution velocity) of myelin result in what action? | saltatory conduction of action potential between node of ranvier, where there are high concentration of sodium channel |
what makes myelin in CNS? | oligodendrocyte |
what makes myelin in PNS? | schwann cells |
each schwann cell myelinate how many PNS axon? | 1 PNS axon |
function of schwann cell (similar to wallerian degeneration) | promotes axonal regeneration |
schwann cell derived from where? | neural crest |
proper function of schwann cell? | increase condution velocity via saltatory conduction at node of Ranvier, where there is high concentration of Na+ channel |
schwann cells are destroyed in what disease? | Guillian barre syndrome |
where is vestibular schwanoma(acoustic neuroma) located? | located in the internal acoustic meatus(CN VIII) |
if acoustic neuroma is bilateral what is it associated with? | associated with Neurofibromatosis type 2 |
each oligodendrocyte myelinate how many CNS axon? | multiple axon (upto 30) |
what is the predominant glial cell in white matter? | oligodendroglia |
how does oligodendroglia appear on H & E? | fried egg apprearenace |
what are the disease if oligodendroglia is injured? | MS / Progressive multifocal leuckoencephalopathy (PML) / leukodystrophies |
oligodendroglia derived form what? | neuroectoderm |