Altered cell volume regulation, caused by the impaired permeability of the cell membrane, leads to sodium retention and substance accumulation within the cell. Sodium attracts water, and the cell swells even more. Protein synthesis is decreased in injured cells. Potassium has difficulty entering the cell and accumulates in the serum, due to loss of the ATPase sodium/potassium pump. Bleb formation occurs in the cell that is already swollen and ready to burst.