3.7 PNS stuff

Question 1

myopathy

Answer 1

pathology in muscle

Question 2

neuropathy

Answer 2

nerve is damaged

Question 3

fascicular plexus

Answer 3

conjunction of fascicles

Question 4

issues associated with myopathy

Answer 4

• muscle fiber degeneration

- motor unit problems: fiber isn’t getting input

Question 5

What can be used to determine if it’s a myopathy or neuropathy?

Answer 5

EMG/NCV

Question 6

What does EMG measure? What are the electrodes?

Answer 6

nerve activity

• stimulating electrode
• recording electrode

Question 7

How is an EMG interpreted?

Answer 7

compare to established norms for nerve conduction speed

Question 8

EMG below norm

Answer 8

neuropathy

Question 9

EMG above norm

Answer 9

myopathy

Question 10

purposes of botox injections

Answer 10

• cosmetic reasons
• migraines
• spasticity
• excessive sweating

Question 11

How can botox help with migraines?

Answer 11

can be used to relax trigger points that may cause migraines

Question 12

What do the issues addressed by botox have in common?

Answer 12

• NMJ with motor end plates

- EVERY muscle fiber has a motor end plate

Question 13

How does botox work?

Answer 13

inhibits ACH release at NMJ

Question 14

botulism toxin: bacteria

Answer 14

• anaerobic bacteria

- avoid bent cans that are puffy

Question 15

What can happen with botulism infection?

Answer 15

systemic paralysis

Question 16

mini endplate potential

Answer 16

• something that happens at the NMJ that helps support muscle health
• contributes to muscle tone

Question 17

What happens at each spike on a mini endplate potential?

Answer 17

one packet of ACH is released

Question 18

axonal regeneration speed

Answer 18

1-2 mm per day

Question 19

axonal regeneration (CNS/PNS)

Answer 19

happens in the PNS, not the CNS

Question 20

severance neuropathy

Answer 20

axon is severed

Question 21

severance neuropathy: proximal stump

Answer 21

• axonal sprouts grow out toward the distal stump

- intact cell body

Question 22

What must be the case for regeneration to occur?

Answer 22

the cell body MUST be intact

Question 23

What happens when there’s a nerve injury?

Answer 23

get immune cell recruitment to clear debris left over

Question 24

What special chemicals do Schwann cells secrete?

Answer 24

• chaemotactic factors

- neurotrophic factors

Question 25

chaemotactic factors

Answer 25

promotes growth and helps axon guidance to the correct distal stump

Question 26

neurotrophic factors

Answer 26

growth factors in neurons

Question 27

Why is the CNS not permissive to regeneration?

Answer 27

• no growth factors secreted by glia

- chemotactic factors help with NEW neuronal growth, not regeneration

Question 28

injury to CNS

Answer 28

• glial cells push end feet into the injury and creates a scar (glial scar)
• axons cannot grow through a glial scar