15.7 - Neuromuscular Junctions Flashcards
What a neuromuscular junction is The role of motor units in determining contraction force How neuromuscular junctions trigger muscle contraction The breakdown of acetylcholine at the neuromuscular junction The role of the sarcoplasmic reticulum in muscle contraction
1
Q
What is a neuromuscular junction?
A
Motor neurone meets skeletal muscle fibre
2
Q
What does an action potential at a neuromuscular junction trigger?
A
Muscle contraction
3
Q
What is a motor unit?
A
All muscle fibres supplied by a single motor neurone
4
Q
How is muscle contraction force determined?
A
Number of motor units stimulated
5
Q
What are the stages in neuromuscular transmission?
A
Action potential arrives
6
Q
What happens after acetylcholine binds to receptors?
A
Sodium ion channels open
7
Q
What enzyme breaks down acetylcholine?
A
Acetylcholinesterase
8
Q
What happens to choline and ethanoic acid?
A
Reabsorbed into synaptic knob
9
Q
What is the role of the sarcoplasmic reticulum?
A
Stores and releases Ca2+
10
Q
How does the sarcoplasmic reticulum trigger muscle contraction?
A
Ca2+ channels open
