Neuromuscular Junction

Question 1

What happens when an action potential reaches a neuromuscular junction?
step 1

Answer 1

1. voltage-gated calcium
   channels open, causing
   calcium ions to diffuse
   into the neurone

Question 2

What happens when an action potential reaches a neuromuscular junction?
step 2 - post calcium ions to diffuse into the neurone

Answer 2

2. Synaptic
   vessels to fuse with the
   presynaptic membrane
   and release acetylcholine into the synapse. It diffuses across the synapse and binds with receptors on the muscle cell surface membrane, opening sodium channels

Question 3

What happens when an action potential reaches a neuromuscular junction?
step 3 - post opening sodium channels

Answer 3

3. The muscle fibre

depolarisation causes an action potential and muscle contraction.

Question 4

What happens when an action potential reaches a neuromuscular junction?
step 4 - post muscle contraction

Answer 4

4. Acetylcholinesterase breaks down acetylcholine

Question 5

Neuromuscular Junction VS Cholinergic Synapse - excitatory or inhibitory

Answer 5

NJ - Only excitatory

CS - Can be excitatory or inhibitory

Question 6

Neuromuscular Junction VS Cholinergic Synapse - Links neurones to …

Answer 6

NJ - Links neurones to muscle

CS - Links either neurones to neurones or neurones to other effectors

Question 7

Neuromuscular Junction VS Cholinergic Synapse - Action potential journey

Answer 7

NJ - action potential ends here
CS - another action potential may
be generated along the postsynaptic neurones

Question 8

Neuromuscular Junction VS Cholinergic Synapse - Which neurones?

Answer 8

NJ - Only motor neurones

CS - Intermediate, motor and sensory neurones

Question 9

Neuromuscular Junction VS Cholinergic Synapse - Acetylcholine binding

Answer 9

NJ - Acetylcholine binds to receptors on the membrane of the muscle fibre
CS - Acetylcholine binds to receptors on the membrane of the postsynaptic neurone