PNS

Question 0

What are fascicles enclosed by?

Answer 0

Perineurium

Question 1

Name the 2 types of somatic sensory (primary afferents)

Answer 1

C fibres (unmylinated, slow)
A delta (myelinated, faster)

Question 2

What holds fascicles together?

Answer 2

Epineurium

Question 3

What else is contained in the epineurium?

Answer 3

White adipocytes (protection)

Blood vessels (many anastomoses)

Question 4

Describe what happens to the blood vessels in diabetic neuropathy

Answer 4

Endothelial cells & smooth muscle cells lining the vessels hypertrophy
Closes lumen
Restricts blood flow

Question 5

Describe the strength of the perineurium and the only thing that can transverse it

Answer 5

Tough
Resistant to pressure
Blood vessels

Question 6

What allows nerves to pass through infected areas of the body unaffected?

Answer 6

Perineurium

Forms a barrier to infection

Question 7

What is the endoneurium made of?

Answer 7

Collagen & ECF

Question 8

Where are macrophages found in peripheral nerves?

Answer 8

Epineurium & endoneurium

Question 9

What is the difference between oligodendrocytes & Schwann cells?

Answer 9

Oligo= CNS, myelinate several axons

Schwann= PNS, myelinate one axon

Question 10

What do Schwann cells secrete?

Answer 10

A glycoprotein called Laminin

Question 11

Laminin is important in nerve regeneration. How?

Answer 11

Provides a surface along which to grow.

Angiogenesis must occur- Laminin provides surface for new blood vessels to grow.

Question 12

What organelles are responsible for axonal transport?

Answer 12

Neurotubules, held together by tau

Question 13

Over expression/ destruction of tau will stop what?

Answer 13

Axonal transport
Molecules produced in the cell body are unable to leave, neurone dies
Happens in Alzheimer’s

Question 14

Name the 2 types of axonal transport

Answer 14

Orthograde (cell body–>terminal/synapse)

Retrograde (terminal/synapse–>cell body)

Question 15

Name the molecular motors involved in orthograde & retrograde axonal transport

Answer 15

O= Kinesin

R= Dynein

Question 16

Name the 2 types of orthograde axonal transport & what each transports

Answer 16

Fast- small molecules (enzymes required for NT production.

Slow- larger structures.

Question 17

Name the 3 categories of peripheral nerve damage

Answer 17

Contusion/bruising (temporary)
Crushing (distal axons will degen)
Severing (distal axons will degen)

Question 18

Describe Wallerian degeneration & the regeneration that follows

Answer 18

Axons distal to injured nerve degenerate but M sheath remains = friendly environment, encourages growth of new As. As from prox side of injury sprout, grow towards empty Schwann cell tubes. Sprout grows into intact endoneurium, attempt to form new A.

Question 19

What helps the axon sprouts proximal to an injury grow towards empty Schwann cell tubes after ‘Wallerian degeneration’

Answer 19

Growth factors produced by Schwann cells

Question 20

What 3 factors affect how good regeneration is?

Answer 20

1) How clean the damage is
2) Whether there is adequate blood supply
3) Age

Question 21

What IS neuropathic pain?

Answer 21

A pain experienced when regeneration is not complete/perfect. Spontaneous/evoked by movement. Tenderness/burning/tingling.

Question 22

What CAUSES neuropathic pain?

Answer 22

Regenerated axon may form a swelling = neuroma, on sensory fibres regenerating into skin. New section of axon has a new mem but distribution of ion channels isn’t perfect = As generate abnormal APs, go to chord, cannot interpret abnormal info, consequence = NP!