Action Potential

Action Potential

Author: Meg O'Mahony

In order to demonstrate an understanding of the Action Potential along a neuron, you need to be able to:

  1. explain, with the use of labelled diagrams and a written explanation, the conduction of the nerve impulse  
    • along the neuron including
      • membrane potential,
      • resting potential,
      • depolarization,
      • gated channels Na+ and K+,
      • threshold potential,
      • action potential,
      • refractory period


In thus tutorial you will learn how the self-propogating electrochemical impulse known as the Action Potential is generated and how it travels along an axon in one direction only. The tutorial will begin with an explanation of how the Resting Potential of -70mV (across the axonal membrane) is generated based on the ions present, passive transport membranes present and the biophysical structure and size of the neurons - with emphasis on the axon.  The different types of transport proteins (leaky channel, antiport active transport and voltage gated channel) in the membrane are explored with their role in the membrane homeostasis. The advantage of Saltatory conduction closes the tutorial.

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The Action Potential

The Action Potential is the proper name for what we often call a nerve impulse. It is a neurochemical process by which ions move to either side of a plasma membrane then are returned to "normal". Look for where Homeostasis exists with the Action Potential.
In class, you will be participating in a hands-on modelling of the Action Potential to make this fairly abstract concept more concrete.

Source: M. O'Mahony, open source images

Student Notes Template

Template for students to take notes from tutorial video. Includes the various figures.


Source: M. O'Mahony, open source images

Dr. Art - The Neuron Blues

Here are the words to this review song :-)


Source: by Thomas Schumann and Arthur W. Siebens, Ph.D., Copyright 2001

Electrical Activity of Neurons

This "Click and Learn" activity from HHMI provides an excellent extension to this tutorial and provides a solid background for the virtual lab that you will be doing in class.

Source: HHMI - url above.

Neurophysiology Virtual Lab

This Virtual Lab from HHMI: 

In this virtual lab, you will record electrical activities of individual neurons, identify by response to stimuli, and use dyes to visualize their morphology. You will be recording electrical activities of individual neurons when you deliver mechanical stimuli to the attached skin. Injecting flurescent dyes into the neurons will let you visualize their morphology. You will dentify the neurons based on the morphology and the response to stimuli, comparing them to previously published results.

The following backgrounds are available:

Background Information About the Leech
Background Information About the Nervous System
Background Information About Electrical Equipment

Source: HHMI - website above