The iWorx newsletter is a FREE monthly publication dedicated to sharing teaching laboratory techniques and other useful information with educators in the fields of Anatomy and Physiology. We will also be sending you technical information and info on new developments at iWorx that we feel may be of use to you in your teaching and research activities.

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iWorx has everything you need to add excitement and distance learning to any physiology teaching program. Our products include data acquisition hardware, professionally -developed physiology courseware, innovative web tools, and a full selection of transducers, cables, front ends and accessories.

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April 2006

  Experiment:  Summation, Tetanus, and Fatigue in an Intact
  Nerve-Muscle Preparation

The most convenient way to examine the properties of a motor unit is to use a nerve-muscle preparation. Since the nerve is still attached to the muscle that it innervates, a stimulator can be used to generate action potentials in the axons that compose the nerve. In the typical junction between nerve and muscle fibers, the signal from nerve is transmitted to the muscle through the release of molecules from vesicles at the end of the nerve fiber. The molecules, known as neurotransmitters, migrate across a gap or synapse between the membranes of the nerve and muscle fibers. The neurotransmitters bind to receptor molecules on the muscle fiber membrane, which activates the flow of ions and currents through the muscle membrane and triggers a muscle fiber contraction. These connections are minute and delicate, but a preparation like the one used in this experiment reduces the possibility of damage to the nerve, muscle, and neuromuscular junction.

In this experiment, the muscle is stimulated directly or through its nerve in a preparation that requires minimally invasive procedures. The exercises demonstrate the effects of recruitment, wave summation, tetanus and fatigue. The site of fatigue is also determined, as well as the effect of an agent that blocks the binding of the neurotransmitter used in the neuromuscular junction.

Download high resolution  press optimized or low resolution screen optimized Summation, Tetanus, and Fatigue in an Intact Nerve-Muscle Preparation Experiment (PDF file).

Tech Note:  A-SE-100 Sleeve-Type Stimulating Electrodes

The A-SE-100 is a stimulating electrode assembly that can be placed on a nerve that is still located within the experimental animal. The probe, with its two silver wire electrodes, is held on the nerve by a soft plastic sleeve that also presses the nerve against the electrodes for improved conductivity. This type of electrode allows studies involving nerves and muscles to be conducted on sensitive tissue without the need for traumatic removal of the tissue from the specimen.

Learn more about the
A-SE-100 from this
tech note.

For a limited time, iWorx is offering its customers a 30% discount on purchase of the A-SE-100 Sleeve Type Stimulating Electrode until May 31, 2006.  Customers in the U.S. and Canada can order directly online.

A-SE-100

Sleeve Type
Stimulating Electrode

$75

$52

  Users Area: Log-in or Register for Access to LabScribe
  Installers, Lab Manuals, and Settings Files.

Whether you plan to download any of the experiments announced in recent editions of the iWorx Newsletter or a new copy of the LabScribe Installation CD, you need a password and an ID to access the download sites for these items. 

To register for a new ID and password, please go here.   After you receive confirmation that user account has been activated, return to the same site and click on the Enter link. 

Registered users can log-in here.

To download screen or press optimized copies of the latest lab experiments and Tech Notes published in the iWorx Newsletters, go here and select the lab experiment of interest.

If you plan to use any of the experiments or manuals announced in recent editions of the iWorx Newsletter, you should obtain a copy of the settings group used to configure LabScribe for these experiments.  To download the settings file, right click here and choose "Save Target As" in the Internet Explorer browser or "Save Link As" in the Firefox browser.  Save the file in your LabScribe Folder.  When you launch LabScribe, the settings group will be available from Load Group command in the Settings menu.

Web Resources

Learn more about neuromuscular junction, summation, tetanus, and fatigue from our external Web resources page.

On this page we have also accumulated a host of links to informative, external physiology Web sites and conveniently categorized them into major sub categories for easy reference.

We are pleased to announce the launch of our new e-commerce Web site for data acquisition and analysis solutions for the life sciences.  Please visit us at www.iworx.com.  Customers in the U.S. and Canada can now purchase many of our physiology teaching products and replacement components directly online.  See all special offers currently running.

Special offer:  Get free shipping for any online purchases over $50 until May 1, 2006.

Clearance Items

iWorx has a large supply of new and trade-in items at up to 70% discount.  Also check with us about trade in allowances for your older Powerlab or Biopac equipment.  Customers in the U.S. and Canada can order directly online. See specials