Question

When the cardiac muscle cell is at rest, the concentration of _____________ is greater on the outside of the cell?

Answer 1

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+).