Nerve physiology

Question 1

Ordered arrangement of nerve anatomy- out to in

Answer 1

• Epineurium
• Perineurium
• Endoneurium

Question 2

Local anaesthetic uses

Answer 2

• Topical
• Local infiltration
• Field block
• Nerve block
• Spinal nerve block
• Epidural nerve block

Question 3

What do Local anaesthetics do?

Answer 3

Prevent or relieve pain

• Stop sensory conduction
• Membrane stabilisers
• Bind Na+ channels

Question 4

Rapid and slow anesthetics

Answer 4

Lidocaine with a rapid onset and short duration of action

Bupivicaaine has a slower onset of action but LASTS longer

Question 5

Sequence of blockade of sharp pain

Answer 5

Cold
Warmth
Touch
Conduction in moor fibres most common

Question 6

Why can you not put adrenaline on the fingers?

Answer 6

It is an end organ and you cannot induce vasoconstriction in end organs
Can’t put adrenaline in tips of ears and penis

Question 7

Maximum doses of lidocaine, bupivicaine and both combined with adrenaline

Answer 7

Lidocaine- 3mg/kg
Lidocaine+ adrenaline 7mg/kg

Bupivicaine 2mg/kg
Bupivicaine+ adrenaline 2.5mg/kg

Question 8

Role of Botulinum, atracurium, suxamethonium

Answer 8

Botulinum- blocks Ach release
Atracurium- non- depolarising
Suxamethonium- depolarising

Question 9

Characteristics of non-depolarising agents

Answer 9

Competitive antagonist
Block the action of Ach
Not broken down
No fasciculations

Question 10

Characteristics of depolarising agents

Answer 10

Single type in clinical uses
Competitive agonist
Act in addition to Ach
Slowly broken down 
Fasiculations

Question 11

What is the Seddon classification

Answer 11

Classification of nerve injury
Neurapraxia- myelin damage, conduction slowed
Axonotmesis- loss of axonotmesis

Neurotmesis- loss of entire nerve trunk, no conduction