Exam 2 Neural TE

Question 1

Describe the differences between CNS and PNS.

Answer 1

• CNS: Brain and spinal cord, limited regeneration, protected by the blood-brain barrier.

PNS: Nerves outside the CNS, better regeneration potential, connects CNS to limbs and organs.

Question 2

What do neurons do?

Answer 2

transmit signals

Question 3

Describe CNS Glial Cells.

Answer 3

Astrocytes (support), oligodendrocytes (myelination), microglia (immune).

Question 4

Describe PNS Glial cells.

Answer 4

Schwann cells (myelination and regeneration), satellite cells (support).

Question 5

What is the function of a myelinated axon?

Answer 5

Insulation for faster signal transmission.

Question 6

What is the function of the nodes of ranvier?

Answer 6

Gaps in myelin where ions exchange, enabling rapid “jumping” conduction (saltatory conduction).

Question 7

Explain differences in the regeneration capacity of PNS and CNS.

Answer 7

The PNS has more regenerative capacity than the CNS (mammalian). CNS regeneration is limited by inhibitory signals

Question 8

How does CNS and PNS regeneration capacity affect the TE approach?

Answer 8

TE for CNS focuses on overcoming inhibitory signals, while PNS TE focuses on guiding and enhancing natural regrowth.

Question 9

What are the current “treatments” for spinal cord injuries?

Answer 9

• neuroprotection in acute period (e.g.,
  steroids), with little hope of regeneration
• Secondary injury cascade results in an
  environment inhibitory to regeneration
• Current treatments do not promote
  axonal regeneration or restore axonal
  circuitry

Question 10

What are the treatment options for PNS injuries?

Answer 10

• Short nerve gaps (<5 mm),
  can suture together
• Larger gaps, use autografts (limited by donor source)
• Acellular grafts
  from allogeneic source
  Synthetic guidance channels

Question 11

What are the limitations that treatment options for PNS injuries have?

Answer 11

Poor functional recovery over long gaps, donor site morbidity.

Question 12

How does the TE approach apply to neural TE (cells)?

Answer 12

• Neural progenitor cells to generate new neurons and glia.
• Supporting cells like Schwann cells to promote growth and remyelination.

Question 13

How does the TE approach apply to neural TE (signals)?

Answer 13

• NGF (nerve growth factor): Most potent for neural regeneration.
• GDNF, BDNF, CNTF: Also support survival and growth of neurons.

Question 14

Briefly describe any of the current nerve conduit options available (you can refer to the video)