Frog Muscle Lab Report

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A single frog leg that was severed from the body at the hip joint was dissected to isolate and expose the gastrocnemius muscle. The gastrocnemius muscle was first separated from the tibiofibula bone, but left attached to the knee and the Achilles tendon. A 15 cm long piece of strong thread was tied tightly around the Achilles tendon of the heel of the frog for later attachment of the muscle to the force transducer equipment. The Achilles tendon below the tied string was then severed and the tibiofibula and femur bones were cut away and removed.
The gastrocnemius muscle was kept moist in Ringers Solutions until being mounted in the ADInstruments Frog Muscle Setup (ADInstruments LabTutor® 2.1).
The ADInstruments Frog Muscle equipment was connected to computers running the LabTutor software. A retort stand was used with a muscle holder mounted onto it and a force transducer was mounted in the micropositioner mounting bracket to measure the force generated by the muscle during simulations. The force transducer was
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Beginning at a stimulus voltage of 0.05 V, the voltage was increased by increments of 0.05 V for each new record. The muscle was stimulated by one pulse in a 625 ms period after an initial 50 ms delay, each record. The minimum stimulus voltage that resulted in a measurable muscle contraction was the threshold voltage. Records were collected until three successive stimuli of increasing voltage did not increase the force generated by the resulting muscle contractions. The stimulus voltage applied to the muscle at the point where increased voltage strength ceased to increase force generation was the maximum excitation voltage of the muscle. The maximum excitation voltage determined the supramaximal excitation voltage that was applied to the muscle in the following experiments (ADInstruments LabTutor®

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