Question

1. Please describe the signal transmission across a myoneural junction that allows the nervous system to move the muscles of a football player during a game? Please be detailed with your description. Hint: Review your video worksheets from your lesson for details on nerve impulse transmission. (5 points)

Answer 1

1. Action potential reaches the axon terminal and depolarizes it.

2. Depolarization opens voltage-gated calcium channels, enabling influx of Ca into the neuron.

3. Calcium binds to specialized proteins on vesicles (containing pre-made acetylcholine) and triggers them to fuse with the neuron membrane at the synapse.

4. Exocytosis of acetylcholine into the synaptic cleft occurs.

5. Acetylcholine diffuses across the synapse and binds to nicotinic receptors on the end plate of the myocyte.

6. Activated nicotinic receptors, themselves ion channels, cause cation influx into the myocyte and generate an end plate potential. This eventually gives rise to the full depolarization within the myocyte that enables contraction.