arrange these events in transmission of an impulse from a motor neuron to the sarcolemma of a muscle cell according to the order that they occur, beginning with the arrival of a signal at the axon terminal. instructions choice 1 of 6. calcium ions are released from the sarcoplasmic reticulum. toggle button calcium ions are released from the sarcoplasmic reticulum. choice 2 of 6. a nerve signal arrives at the axon terminal. toggle button a nerve signal arrives at the axon terminal. choice 3 of 6. electrical signals spread down t tubules. toggle button electrical signals spread down t tubules. choice 4 of 6. ach binds to receptors in sarcolemma. toggle button ach binds to receptors in sarcolemma. choice 5 of 6. ach diffuses across the synaptic cleft. toggle button ach diffuses across the synaptic cleft. choice 6 of 6. synaptic vesicles release acetylcholine (ach). toggle button synaptic vesicles release acetylcholine (ach).