2 L13 Nerves and the Neuromuscular Junction

Question 1

NMJ sequence of events

Question 2

Structure of nicotinic AchR

Answer 2

5 subunits, each with 4 transmembrane domains. Subunits surround pore in membrane - Pore is gated and usually closed

Question 3

True or False- there are differences between muscle and neuronal nicotinic AchR

Answer 3

True

Question 4

How is nicotinic AchR opened

Answer 4

Chemically gated- when 2 Ach bind - Depolarisation due to Na entry

Question 5

What kind of channel is nicotinic AchR and what is it permeable to

Answer 5

Non-selective cation channel that is permeable to potassium and sodium

Question 6

NMJ agonists and antagonists

Answer 6

Agonist- nicotine
Antagonists- a- Tubocurarine, alpha neurotoxins

Question 7

What kind of disease is Myasthenia gravis

Answer 7

Autoimmune disease of the NMJ

Question 8

What happens in Myasthenia gravis

Answer 8

Antibodies attack nAchR, blocking and reducing receptor number. This causes an inflammatory response that damages the endplate - NMJ function is reduced, leading to weakness of frequently used muscles