Neuromuscular junction

Question 1

Question 2

1.

Answer 2

An action potential in a motor neuron is propagated to the terminal button

Question 3

2.

Answer 3

This local action potential triggers the opening of voltage gated Ca2+ channels and the subsequent entry of Ca2+ into the terminal button

Question 4

3.

Answer 4

Ca2+ triggers the release of acetylcholine (ACh) by exocytosis from a portion of the vesicles

Question 5

4.

Answer 5

ACh diffuses across the space separating the nerve and muscle cells and binds with the receptor-channels specific for it on the motor end plate of the muscle cell membrane

Question 6

5.

Answer 6

This binding brings about the opening of these nonspecific cation channels, leading to a relatively large movement of Na+ into the muscle cell compared to smaller movement of K+ outward

Question 7

6.

Answer 7

The result is an end-plate potential. Local current flows between the depolarised end plate and the adjacent membrane

Question 8

7.

Answer 8

This local current flow opens voltage-gated Na+ channels in the adjacent membrane

Question 9

8.

Answer 9

The resultant Na+ entry reduces the potential to threshold, initiating an action potential, which is propagated throughout the muscle fibre.

Question 10

9.

Answer 10

ACh is subsequently destroyed by acetylcholinesterase, an enzyme located on the motor end- plate membrane, terminating the muscle cell’s response

Question 11

https://www.youtube.com/watch?v=CLS84OoHJnQ

Question 11

https://www.youtube.com/watch?v=CLS84OoHJnQ