Complete each sentence with the correct word Sodium ions Na

Complete each sentence with the correct word. Sodium ions (Na^-) synaptic cleft ligand-gated ion channels diffusion voltage-gated K^+ channels voltage-gated Ca^2+ channels motor end plate Calcium ions threshold exocytosis voltage-gated Na^- channels Sodium ions An action potential reaches the axon terminal causing _____ to open. _____ enter the axon terminal leading to the release of acetylcholine via _____. Acetylcholine diffuses across the _____ before binding to its receptor located on the _____. Acetylcholine receptors function as _____. In response to acetylcholine binding, _____ move into the muscle fiber causing the membrane potential to rise. When the membrane potential reaches _____ an action potential spreads across the sarcolemma due to the opening of _____.

Solution

Answer:

1. An action potential reaches the axon terminal causing voltage-gated Ca²⁺ channels to open.

2. Calcium ions enter the axon terminal leading to the release of acetylcholine via diffusion.

3. Acetylcholine diffuses across the synaptic cleft before binding to its receptor located on the motor end plate.

4. Acetylcholine receptor function as ligand-gated ion channels.

5. In response to acetylcholine binding, sodium ions (Na⁺) move into the muscle fiber causing the membrane potential to rise.

6. When the membrane potential reaches threshold an action potential spreads across the sacolemma due to opening of .voltage gated Na⁺ channel.