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MSK I > Integration-Neuromuscular > Flashcards

Flashcards in Integration-Neuromuscular Deck (9)

What causes the degenerative effects of multiple sclerosis?

Immune-mediated inflammation, destruction of myelin and consequential axon loss


What virus has been found to kick-off multiple sclerosis?

Epstein-Barr virus. It may initiate the inflammatory response that activates chronic inflammatory cells (activated macrophages) that cause degeneration of neurons.


What drug is prescribed as a result of demyelination of axons?

Dalfampridine. It blocks the exposed K+ channels that were originally covered by the myelin sheath.


How do astrocyte defects cause the effects of multiple sclerosis?

Glutamate pump is defected and levels build up near the axon and damage the myelin sheath.


How can you help nerves to remyelinate after axon damage?

Oligo precursor cells proliferate and migrate to demyelinated axons. Mature oligodendrocytes do not repair.


What happens to axons after a nerve is cut in the CNS?

They degenerate and are eaten up by macrophages.


What happens to axons after a nerve is cut in the PNS?

Schwann cells lay down a pathway for regeneration in an area cleared by macrophages.


What is your goal when doing a nerve graft?

Clear a pathway for the axon to grow down back to its original place.


What happens to muscle if innervation is impaired?

Atrophy and a change from glycolytic fibers (type II) to oxidative fibers (type I).