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Building the nervous system > Regeneration > Flashcards

Flashcards in Regeneration Deck (12)
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What causes tail regeneration in xenopus tadpoles

BMPs during a critical refractory period


What is the result of a peripheral nerve injury close to the soma

More likely to result In cell death - retraction of processes, chromatolysis


What is the result of a peripheral nerve injury to the proximal axon

Reorganisation and re-expression of immature features i.e. tubulins


What id the result of a peripheral nerve injury to the distal axon

Disintegration and death - macrophages move in to clear debris


What effect does peripheral nerve injury have on the denervated muscle

Atrophy of muscle
AchR revert to their embryonic types - increased levels of MUSK


How is a peripheral nerve injury regenerated

Macrophages remove damaged myelin
Mitosis of Schwann cells supply growth factors causing formation of Band of Bunger - rows of Schwan cells to guide axon regrowth
Undamaged nearby neuron in area sends projections to cover the damage and target denervated muscle


How do crush and cut injuries differ in the ability for regeneration

Crush - ECM and basal lamina remain intact allowing for easier regeneration
Cut - Makes regeneration harder/impossible - sutured nerves may not regrow accurately


What are the results of spinal cord injuries

Sprouting followed by failed regeneration and subsequent degeneration - cysts and glial scars form


Why is regeneration so poor

Inhibitory myelin - CNS neurons avoid oligodendrocytes in vitro - myelin proteins produce nogo-a which inhibits axon growth


What is the role of nogo-a

Critical inhibitory protein in CNS - KO or anti-nogo leads to partial decrease in inhibition of axon regrowth


What role do astrocytes have in preventing regeneration

Formation of glial scarring
attachment to astrocytes impairs their regeneration


What are spinal bridges

Artificial structures that bypass lesions - filled with growth factors, ECM and synthetic matrix