Regeneration in the NS Flashcards
Why is regeneration in the NS important?
Large number of traumatic injuries in peripheral nerves annually
What are some causes of peripheral nerve damage?
- Spinal cord injury
- Stroke
- Degenerative diseases
- Road accidents
What is the regenerative capacity of lower animals (reptiles, amphibians, fish)?
Huge
How is xenopus tadpole tail regeneration triggered?
By BMPs
What is the ‘critical period’ of regeneration in the tadpole?
Time after this, there is a loss of BMP expression and the trail cannot regenerate
In lower animals, what is regeneration dependant on?
What are exceptions to this?
Nerves
Worms - if cut in half, both ends grow back
What is a blastema?
What is in close proximity to it? What does this allow?
Pluripotent stem cells in a salamander
In close proximity to nerves - where Schwann cells migrate in from and allow regrowth
In a nerve, what do the insulating layers impact on?
The damage the nerve can get and the ability of the nerve to repair itself
Who classified nerve injuries?
Seddon
What is Neuropraxia?
Damage to some of the insulating layers of the nerve - produced by compression or stretching
What does neuropraxia affect?
Conduction of the nerve (because of damage to the insulating layers)
What is axonotmesis?
Division of the nerve but the connective tissue remains intact
Nerve is resected
What is neuromesis?
Division through the entire nerve (through insulating layers and through the axon)
How was Seddons classification of nerves expanded?
At the level of axontemeis and neuromesis, can have different stages of conduction - some preservation or complete loss
What happens if the injury happens close to the cell body? (In the PNS)
Get cell death
What happens if the injury is not close to the cell body?
In the PNS
Re-organisation and re-expression of immature features (tubulin), depending upon the level of damage