Skeletal Muscle Lab Report

INVESTIGATION OF PHYSIOLOGICAL & MECHANICAL PROPERTIES OF SKELETAL MUSCLE USING FROG GASTROCNEMIUS
AIM
The purpose of this experiment was to demonstrate the physiological as well as mechanical properties of skeletal muscle using the gastrocnemius muscle of a frog by exploring five different investigations namely the single twitch, the graded response, the relationship between muscle length and tension, muscle tetanus, and muscle fatigue. These individual experiments aim to explore the way muscles can contract when an electrical stimulus is applied, illustrate stimulation of motor nerves can contract skeletal muscles and to assess the extent sarcomeres can lengthen when force of contraction is applied.
INTRODUCTION
Skeletal muscle is one of
This movement passes along the T-tubules where it triggers the release of Ca2+ allowing the thick and thin filaments to interact. As such sarcomeres are shortened pulling the ends of the muscle fibres to be close together. Tension of a muscle fibre production is directly related to the length of a sarcomere. Therefore a muscle is stimulated at its greatest length when tension generated is at its maximum. Similarly tension produced is most efficient when the maximum number of cross-bridges form its optimal resting length (Martini
Repeated stimulation prior to the end of relaxation phase can produce wave summation where a single twitch is added to another. Incomplete tetanus is likely to take place when this occurs whilst complete tetanus will occur where the relaxation phase is completely removed. This will lead to muscle fatigue, where an active skeletal muscle can no longer continue to perform its muscle movements (Martini 2015). A recovery period may be required for the muscle fibres to revert to the natural pre-exertion level.

The experiment will examine the properties of skeletal muscles by its activity under varying conditions such as the effects of stimulus intensity & frequency on the contraction force where electrical current is applied to frog's gastrocnemius muscle. The muscle twitch contraction is then measured with a single electric stimulus, multiple stimuli applied close to one another, the summation, tetanus and fatigue stages of the muscle contraction.

MATERIAL AND METHODS
The materials and method for this experiment followed James Cook University PC1001 Human Anatomy and Physiology 2017 week 8 lab notes. The procedures followed all step from the manual without any modification or deviation. Complete procedure that details the experiment can be found in the Learn JCU website. The outcome of the experiments were documented