The ability of muscles to exert themselves repeatedly is referred to the muscle endurance. Here, the muscles do not get fatigued and work continuously. Muscle endurance is due to ability of the muscles to obtain better supplies of oxygen and nutrients which in turn ensure that the muscles exert themselves without any fatigue.
Stimulation of a neuron causes a change in the charge inside the cell from negative to positive. This change is caused by ions, which are atoms with an electrical charge, moving across the cell. This change within the cell is consistent with the definition of an electric charge.
