Neuronal Regeneration Flashcards
CNS can repair well T/F
F
Why cant the CNS repair well?
Oligodendrocytes inhibit neuronal growth
Astrocyte Gliosis
Glial Scar
Phagocytes breakdown myelin more slowly
The distal part of a regenerating axon extends proximally to repair T/F
F, the proximal part extends distally
What is gliosis?
Expansion of the glia due to neuronal damage
Define Sprouting
Expansion of the neuronal process of nearby axons after injury. Provides a limited improvement in functionality
When is better repair achieved when the axon is cut or crushed? why?
Crushed. Myelin and Schawn cells can act as guide for axon regrowth
Mechanism to help heal the axons in the PNS
Microsurgery
What is chromatolysis and when does it occur?
In the first 1-2 weeks after injury. Loss of the Nissl substance after neuron damage
What is the Nissl substance?
RER and Ribosomes close to the nucleus of the neuron
Neuron histological look after 1-2 weeks of injury?
Nucleus is peripheral
Chromatolysis
Wallerian Degeneration
What is Wallerian Degeneration?
Retrogade degeneration from the distal part of the axon to the proximal part
what can be seen 3 weeks after neuronal injury?
increased Nissl substance
nucleus is central
increased schawn cell proliferation
axon growth towards distal end
what can be seen 3 months after SUCCESSFUL neuronal injury?
electric conductivity restored
if neuronal regeneration is unsuccessful what can be seen?
Neuroma formation. Distal bloob of axon. Sometimes painful
What are neurotrophins?
molecules that stimulate neuronal growth and repair
Glial Scar Formation is…
A barrier between the damaged and healthy tissue
Glial Scar Formation is formed by…
deposition of extracellular matrix that inhibits neuronal growth by the astrocytes
one of the main inhibitors of Neuronal Growth is?
Condroitin Sulphate Proteoglycans (CSPs)
What are some of the substances found in myelin that inhibit neuronal growth?
Nogo, proteins
They all bind to NOgoR
What is the main function of the proteins that inhibit neuronal growth?
decrease neuronal sprouting and keep axons healthy
When are axon guidance molecules present?
During development
During CNS repair what do astrocyte present in gliosis that inhibit neuronal growth?
guidance molecules get upregulated on the astrocytes
What is the main function of the Rho Kinase pathway in neuronal repair?
Blocks the formation of growth cones
What are the two main areas of neuronal regeneration in the brain?
Subventricular Zones of the Lateral Ventricle (SVZ) Subgranular Zone (SGZ) of the Dentate Gyrus of the Hyppocampus
