Channels

Abstract

In the previous chapter it was pointed out that biological cells are enclosed by a plasma membrane. This membrane consists of a lipid bilayer and, as seen in Fig. 3.1, the hydrophilic polar heads are oriented facing the intracellular and extracellular water-containing media while the hydrophobic tails, on the other hand, are internal to the membrane. The biophysical consequence of the lipid is a membrane with the high dielectric constant of oil and the high resistivity of that material. We have noted a membrane capacitance of C _m = 1 μf/cm²; the lipid membrane specific resistance is 10⁹ Ω cm².