NMJs

Question 1

Describe the first four steps of NMJs.

Answer 1

1. An action potential in the motor neuron occurs.
2. Na+ VGCs open in the presynaptic terminal.
3. Vesicles fuse with the surface (Ca2+ dependent exocytosis).
4. ACh diffuses across the synaptic cleft.

Question 2

Describe the middle four steps of NMJs.

Answer 2

5. ACh binds to receptors.
6. Opens ligand-gated Na+/K+ channels.
7. Evokes end plate potential.
8. Membrane depolarises.

Question 3

Describe the last four steps of NMJs.

Answer 3

9. Na+ VGCs open.
10. An action potential occurs in the sarcolemma.
11. Muscle contracts.
12. ACh is cleared up by AChase.