The PhysioEx skeletal muscle simulator: stimulating, measuring, recording data, plotting and checking your answers.

Virtual Lab

The Virtual Lab is a practice simulator for the PhysioEx 9.1 Exercise 2: Skeletal Muscle Physiology dry lab. Use it to prepare for the practicum, or to go over it again afterwards. Its numbers follow the practicum slides (threshold about 0.8 V, maximal stimulus 8.5 V, optimal length 75 mm), but in your report always use the values you measure in the real program.

The seven activities

  1. The Muscle Twitch and the Latent Period
  2. The Effect of Stimulus Voltage
  3. The Effect of Stimulus Frequency
  4. Tetanus in Isolated Skeletal Muscle
  5. Fatigue in Isolated Skeletal Muscle
  6. The Skeletal Muscle Length–Tension Relationship
  7. Isotonic Contractions and the Load–Velocity Relationship

Each activity page has the Background, the Steps to follow, the equipment, the data table, What you should find, and Check your understanding questions with explanations.

Running an experiment

  • Set the controls the activity uses: Voltage, Muscle length, Stimuli per second or Weight.
  • Press Stimulate (or Single Stimulus, Multiple Stimulus and Stop Stimulus where the activity needs a train of stimuli). The trace is drawn on the oscilloscope, slowed down so you can watch it.
  • In Activity 1, press Measure and move the line (on the trace or with its slider) to where the force starts rising: that time is the latent period, and it's saved with the row.
  • Record Data adds the run to the data table. Clear Tracings wipes the screen; up to eight tracings stay on it, each in its own colour.

Your data

  • The table is kept for each activity on this device, so you can come back to it later. Delete removes one row; Clear data empties the table.
  • Plot Data draws the graph the activity asks for (for example force against voltage).
  • Download CSV saves the table for a spreadsheet or your report.

Going further

The walkthrough with expected results is in the physiology ebook: the practicum guide chapter linked at the bottom of the Virtual Lab page. The equations behind the simulator are listed in the developer docs, if you want to check a number by hand.

This is an independent practice tool modelled on PhysioEx; it isn't affiliated with Pearson.

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