Physiology 2130 Lecture Notes - Lecture 4: Resting Potential, Axon Hillock, Electrochemical Gradient
8 Dec 2016
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Document Summary
In the last section, we learned that virtually all cells in the body have membrane potentials, with the inside being electrically negative relative to the extracellular uid. We also learned how this membrane potential is established and maintained by the electrochemical gradients of the major intracellular and extracellular ions. At right is a diagram representing what we know so far about the ion concentrations and electrical distribution of a typical cell. The sizes of the ions represent their relative extra- and intracellular concentrations, and the arrows show the associated concentration gradients for each ion. Always keep this diagram in mind when you think about all of the different membrane potentials. Now its time to see how certain excitable cells in the body put this potential to work. Nerve and muscle cells are considered excitable because they can use the resting membrane potential to generate an electrochemical impulse called an action potential.
