UNFIGURE 14.1.

FIGURE The positively charged potassium ion cannot cross the lipid bilayer, but passes easily through a water-filled tube in a potassium channel.

FIGURE The resting voltage of (A) glial and (B) nerve cells.

FIGURE A nerve cell from the retina viewed with its nutritive capillaries. Red blood cells are an example of cells whose membrane voltage varies little, while nerve cells are specialized to transmit electrical signals over long distances. Image by Professor David Becker, University College London; used with permission.

FIGURE Chloride is close to equilibrium across most plasma membranes.

UNFIGURE 14.2.

UNFIGURE 14.3.

FIGURE The glucose carrier and the sodium/calcium exchanger are sometimes open to the cytosol and sometimes open to the extracellular medium.

FIGURE Action of the sodium/calcium exchanger.

UNFIGURE 14.4.

FIGURE The calcium ATPase undergoes a cycle of phosphorylation and dephosphorylation. These drive shape changes that in turn push calcium ions out of the cell.

FIGURE Action of the calcium ATPase.

FIGURE The connections of a pain receptor nerve cell.

FIGURE One type of pain receptor has a distal terminal in the skin and is connected to the central nervous system by a myelinated nerve fiber.

FIGURE Electrical events in a pain receptor nerve cell.

FIGURE The voltage-gated sodium channel.

UNFIGURE 14.5.

FIGURE Frequency coding in the nervous system.

UNFIGURE 14.6.