Tonight's Reading Made Me Laugh
from The Neuron: Cell and Molecular Biology 3E, by Irwin B. Levitan & Leonard K. Kaczmarek, chapter 3:
The plasma membrane of a nerve cell or, indeed, of any cell provides a resistance to the flow of ions between the intracellular and extracellular compartments. Accordingly, it can be thought of as an electrical resistor, with the membrane resistance, Rm, being measured in ohms (Ω). In addition, the lipid bilayer provides an extremely thin insulating layer between two conducting solutions. This allows the membrane to act as an electrical capacitor, a device that is capable of separating and storing electrical charge. The membrance capacitance, Cm, is measured in farads (F). These considerations allow us to describe the electrical properties of the lipid bilayer membrane simply in terms of an equivalent electrical circuit, as shown in Figure 3-4a. This description is introduced not to torment the student of cell and molecular biology, but rather because it is extremely useful in understanding the electrical behavior of biological membranes under a variety of physiological conditions.
(Bold emphasis mine)