4. Transmission of Nerve Impulse to Muscle - Neurotransmitter attaches to receptors on the sarcolemma, Sarcolemma becomes temporarily permeable to sodium (Na+) that rushes into the cell giving it a positive charge, Sodium rushing into the cell generates an action potential, Once started, muscle contraction cannot be stopped, To return to resting state, Potassium ions (K+) diffuse out of the cell, Sodium-potassium pump pumps sodium and potassium back to their original positions