Proceedings of The Physiological Society
University of Cambridge (2008) Proc Physiol Soc 11, PC48
The Virtual Frog; two computer-based practical classes for teaching neuromuscular physiology.
J. Bagust1, K. Bagust1, I. Brown1, R. Foreman1
1. AECC, Bournemouth, United Kingdom.
Practical classes featuring isolated frog nerve, and nerve-muscle preparations, used to feature heavily in the traditional teaching of neuromuscular physiology to physiology and medical science undergraduates. For a variety of reasons such classes using animal material are becoming more difficult to include in modern curricula. The Virtual Frog classes consist of recordings made from frog (Rana temporaria) isolated sciatic nerve and gastrocnemius muscle preparations during undergraduate practical classes held in 1992. The tissue responses were digitised and recorded in computer data files. These data have subsequently been used to allow students to reconstruct the experiments on standard laboratory PCs. This provides students with the experience of handling real recordings (not mathematical simulations), including noise and biological variation, but without the problems associated with using actual animal tissue. Each program contains an introduction to the equipment and experimental arrangements, before a selection of experiments on that tissue is presented. On selection of an experiment the appropriate data records are displayed on a simulated oscilloscope, and the experimental parameters (eg stimulus voltage or muscle length) can be changed using drop down menus. On-screen cursors can be used to measure times and amplitudes from the displayed waveform. Students are provided with detailed schedules containing spaces into which they are required to enter their measurements, plot graphs and answer questions. These sheets are completed during the course of the practical session, and are subsequently used in an in-depth group de-briefing session with a tutor to reinforce an understanding of the underlying physiological principals. The experiments included in the two programs are: Frog Sciatic Nerve - Gastrocnemius Muscle preparation - Effect of stimulus intensity on twitch amplitude Paired stimuli Genesis of tetanus Twitch length-tension plot Effect of temperature changes on the muscle twitch Effect of curare on the muscle twitch Frog Sciatic Nerve preparation - Effect of stimulus intensity on compound action potential amplitude Paired stimuli and refractory period Measurement of conduction times Direction of conduction Effect of temperature changes on the compound action potential. These programs have been used in undergraduate physiology classes for more than 12 years. They have been well received by the students, enhance their understanding of neuromuscular physiology, and avoid the difficulties associated with providing classes involving animal tissues.
Where applicable, experiments conform with Society ethical requirements