Solar eclipses result from the Moon blocking the Sun relative to the Earth; thus Earth, Moon and Sun all lie on a line. Lunar eclipses work the same way in a different order: Moon, Earth and Sun all on a line. In this case the Earth's shadow hides the Moon from view.
When the cardiac muscle cell is at rest, the concentration of sodium and calcium is greater on the outside of the cell.
The resting membrane potential (the cardiac muscle cell is at rest) is characterized by more negatively charged inside of the membrane comparing to the outside. The main ions found outside the cell at rest are: sodium (Na+), and chloride (Cl−), and Ca2+ whereas inside the cell it is mainly potassium (K+).