Neurohistology and Neuromuscular Junction DD

Question 1

What is a multipolar neuron

Answer 1

Multiple dendrites and one axon

Question 2

What is a bipolar neuron

Answer 2

Has one dendrite and one axon attached to the cell body

Question 3

What is a unipolar neuron

Answer 3

Has one process from the cell body an axon

Question 4

List the 4 main functions of glial cells

Answer 4

• Provides structure for the neurons
• Forms the myelin sheath
• Supplies nutrients and oxygen to neurons
• Destroys pathogens and removes dead neurons

Question 5

What are the glial cells of the PNS

Answer 5

Schwann cells

Question 6

What are the glial cells of the CNS

Answer 6

Oligodendrocytes
Astrocytes
Microglia

Question 7

T or F: Schwann cells myelinate many neurons

Answer 7

False - they only myelinate one

Question 8

T or F: Oligodendrocytes can myelinate many neurons

Answer 8

True - they myelinate many neurons

Question 9

Which type of glial cell is involved in pathologies such as Alzheimer’s disease and MS

Answer 9

Oligodendrocytes and Microglia

Question 10

What is the most common glial cell?

Answer 10

Astrocytes

Question 11

What are the functions of Astrocytes

Answer 11

• Structural support and insulation
• Blood-brain barrier maintenance
• Divide and wall off damaged areas
• Scavengers to remove NT from the synaptic cleft

Question 12

What type of glial cells have a major phagocytic role?

Answer 12

Microglia

Question 13

What are the x roles of microglia?

a) Protective
b) Destructive

Answer 13

a) Mobilize after injury, important for brain development, phagocytosis
b) Alzheimer’s disease and aging, HIV/AIDs

Question 14

Which disease has the oligodendrocytes attacked by their own antibodies?

Answer 14

Multiple Sclerosis

Question 15

What is the etiology of botulism

Answer 15

Neurotoxin produced by C. Botulinium 
From:
- food-borne
-wound
- unclassified

Question 16

How does Botulism poisoning occur

Answer 16

1) Enters presynaptic terminals
2) Blocks fusion of ACh vesicles w/presyn mem
3) Inhibit ACh release into Neuromuscular junction
4) Nerve Impulse fails to transmit
5) Mm paralysis

Question 17

How long until s/s develop w/botulism ? What is the incidence rate?

Answer 17

12-36 hours following ingestion

10 adult and 100 infant each year

Question 18

What are the s/s of botulism?

Answer 18

• Flaccid symmetrical paralysis
• Blurred & double vision, photophobia, ptosis
• Lethargy
• Dry mouth, nausea, and vomiting
• Respiratory mm

Question 19

BoTox use

Answer 19

• Temporarily treat a focal spasticity by preventing the release of ACh from the presynaptic nerve terminal
• Occurs gradullat over 4-7 days and is taken up w/in 12 hours

Question 20

What should we do post-injection of PT?

Answer 20

• Increase mm strength of opposing mm groups

- Do NOT over-stretch the weakend mm

Question 21

What is myasthenia Gravis

Answer 21

Post-synaptic membrane disease at neuromuscular junction that is slow and progressive

Question 22

What is the mechanism of myasthenia gravis?

Answer 22

• widened synaptic cleft, loss of folds
• dec # and density of ACh receptors
• Results in weakness or paresis

Question 23

What are the classifications of MG and percentages

Answer 23

• Ocular myasthenia - confined to extra-ocular mm (10-15)
• Generalized weakness (85)
• Myasthenic crisis (resp failure)

Question 24

s/s of Myasthenia gravis

Answer 24

• ptosis
• diplopia
• facial weakness
• oropharyngeal weakness
• chewing, swallowing and speaking difficulties
• weakness (BUE or LE, respiratory mm, fluctuates)

Question 25

What are some interventions of myasthenia gravis?

Answer 25

• Anticholinesterase drugs
• immunosuppressive drugs
• IVIG
• Plasmaphoresis
• Thymectomy