Repair & Regeneration

Question 1

Generally what are the 3 types of repair?

Answer 1

1. Axon repair of peripheral nerve cell or central nerve cells that project to periphery
2. Restoration of Central nerve cells
3. Genesis of new neurons to replace those that are lost

Question 2

What must occur for restoration of central nerve cells?

Answer 2

• Must be able to regenerate any damaged dendrites & axons
• Requires restructuring of surrounds neurons & glia
• Largely fails because of inhibitory signals from glia

Question 3

What must happen for genesis of new neuron to replace those that are lost?

Answer 3

• Extremely rare
• Neural stem cells must exist in correct location & environment must support migration & neurite growth

Question 4

How do Axons regenerate in the PNS?

Answer 4

• Break in axon causes cell body to swell to accommodate protein synthesis for axon regeneration
• Macrophages clean
• Axon grows through regeneration
• Formation of new myelin sheath

Question 5

What does it mean for CNS damage to be fixed?

Answer 5

Does not reflect a replacement of lost tissue
- Undamaged brain regions are recruited to support the function that was served by damage tissue

Question 6

How are the 3 way damage to CNS occurs?

Answer 6

1. Physical trauma
2. Hypoxia
3. Neurodegenerative disease

Question 7

What do damaged cells of CNS undergo?

Answer 7

Necrosis, which forms a scar & apoptosis which prevents recovery

Question 8

How does glia prevent restoration of dendrites & axons in the CNS?

Answer 8

Chemorepulsion preventing neurite outgrowth
- Glutamate floods damage area = exocitotoxity
- Glial cells invade damaged area & proliferate
- Lead to formation of glial scar

Question 9

Where are new neurons generated from? And where do new neurons form?

Answer 9

• Generated from sub ventricular zone
• Produce new neurons in olfactory bulb & hippocampus