Neural Regeneration Flashcards
(11 cards)
What is Nissl substance?
- How many weeks post injury is it lost?
- What is the term for loss of Nissl Substance?
- Ribosomes actively transcribing RNA
- Lost 2 weeks post injury
- Chromolysis/chromatolysis
Describe appearance of Peripheral NS neuron?
- Central Nucleus
- Dense Nissl substance
Describe appearance of Peripheral neuron 2 weeks post-injury?
- In the cell body
- In the Axon
- Peripheral nucleus
- Chromolysis/Chromatolysis (loss of Nissl substance)
Wallerian Degenernation
- Degen. of Axon + Myelin sheath (below site of injury)
- Debris phagocytosed by Macrophages
Describe appearance of Peripheral neuron 3 weeks post-injury?
- In the cell body
- In the Axon
- Schwann cells proliferate
forming compact cord
Growing axons penetrate schwann cell cord
When does successful regeneration occur?
What does it include?
3 months post injury
- electrical activity restored
- muscle fiber regeneration
What is a Neuroma?
- Unsucessful regeneration of PNS axon.
- A bundle of nerve fibres
- Axon grows but cannot find its target.
- Painful.
- Schwann cells keep secreting growth factors
Factors that influence Regen. capcity of Peripheral nerves?
- Axon crushed (not cut)
-
(CNS) Factors that inhibit regeneration (of central NS nerves)?
- Astrocyte Gliosis (Glial scar)
- Oligodendrocytes
- Myelin inhibitors
(Myelin proteins: Nogo, MAG, OMgp— inhibit axons growth) - Axon guidance molecules
(promote, repel or guide growing axons)
What is a common mediator of inhibition (of regeneration)?
Rho kinase
Describe CNS vs PNS injury environment
(refer to table in slides)
Where are Neural stem/progenitor cells found?
2 regions
1) Sub-ventricular zone (of Lateral Ventricle)
2) Sub-Granular Zone
(in Hippocampus - memory, learning, anxiety)
