Virtual Physiology Lab: PhysioEx Practice

Practise the PhysioEx skeletal muscle dry lab online: stimulate a simulated muscle and record twitch, summation, tetanus, fatigue, length–tension and load–vel…

Skeletal Muscle Physiology

An isolated muscle on a force transducer: stimulate it, change the voltage, frequency, length and load, and record what happens.

1. The Muscle Twitch and the Latent Period: Stimulate the muscle, then measure the delay before force starts to rise.
2. The Effect of Stimulus Voltage: Find the threshold and the maximal stimulus: motor unit recruitment.
3. The Effect of Stimulus Frequency: Stimulate again before relaxation ends and watch the twitches sum.
4. Tetanus in Isolated Skeletal Muscle: Raise the stimulus rate from unfused to fused tetanus and maximal tetanic tension.
5. Fatigue in Isolated Skeletal Muscle: Hold a tetanus until force falls, then rest the muscle and see how much it recovers.
6. The Skeletal Muscle Length–Tension Relationship: Change the resting length and record active, passive and total force.
7. Isotonic Contractions and the Load–Velocity Relationship: Hang heavier weights on the muscle and measure how fast, and whether, it lifts them.