Bioelectricity: The Mechanism of Origin of Extracellular Potentials

In this class, students learn how to think about electrically active tissue in terms of individual mechanisms, and learn to analyze the mechanisms quantitatively as well as describe them qualitatively. The course uses many of the same examples used by Hodgkin and Huxley, who won the Nobel Prize for their experimental unraveling of the mechanisms of the nerve axon of the giant squid, and their creation of a mathematical model of membranes and propagation to understand its function. That work has been the foundational element of most subsequent understandings of electrically active tissue, whether in nerves, the brain or in muscle, including the heart.

Topics covered include:

  • The electrical charging of active membranes from the creation and use of differences in ionic concentrations across the membrane.
  • The stimulation of the membrane, both naturally and from engineered sources.
  • The creation of action potentials by the membrane in response to stimulation.
  • The chain reaction of membrane responses, with each small region or cell initiating an action potential in adjacent ones.
  • The observation of associated electrical currents in terms of extracellular wave voltages they create, the basis of clinical measurements such as the electrocardiogram.


  • Second course in a series that redesigns a 9-week MOOC into a more modular format.



  • Biomedical Engineering
  • Pediatrics

Project Use:


Launch Date:

  • September 2012

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