Question

place the events of excitation of a muscle fiber in order. rank the options below. calcium ions enter the axon terminal through voltage - gated channels. an action potential is generated in the adjacent sarcolemma. na⁺ ions enter, and k⁺ ions leave the cell, creating an end - plate potential. ach diffuses across the synaptic cleft and binds to receptors on the sarcolemma. ach is released into the synaptic cleft.

Explanation:

The process starts with an action - potential arriving at the axon terminal, causing calcium ions to enter through voltage - gated channels. This leads to the release of acetylcholine (ACh) into the synaptic cleft. ACh then diffuses across the synaptic cleft and binds to receptors on the sarcolemma. This binding causes sodium ions to enter and potassium ions to leave the cell, creating an end - plate potential. Finally, an action potential is generated in the adjacent sarcolemma.

Answer:

1. Calcium ions enter the axon terminal through voltage - gated channels.
2. ACh is released into the synaptic cleft.
3. ACh diffuses across the synaptic cleft and binds to receptors on the sarcolemma.
4. Na⁺ ions enter, and K⁺ ions leave the cell, creating an end - plate potential.
5. An action potential is generated in the adjacent sarcolemma.