Fill in the blank: Excitation- coupling represents the physiologic mechanism whereby an electrical discharge at the muscle initiates chemical events at the cell surface, releasing intracellular Ca2+ and ultimately causing muscle action.

What do isotopes of uranium have the same number of? what do they have a different number of? a) same number of protons; different number of electrons b) same number of protons; different number of neutrons c) same number of electrons; different number of protons d) same number of neutrons; different number of protons