Maximum contractile force production dependant on muscle and sarcomere length in isolated sartorius muscle of Rhinella marina
Abstract:
An isolated Sartorius muscle of Rhinella marina was repeatability stimulated with electrical impulses to induce isometric contraction. Contractile forces evoked were measured with a force transducer and the relationship between force and muscle length was investigated through the modulation of sample lengths from 80%-140% of the sample resting length. The data was plotted and the active force produced a characteristic plateau effect, which presented an optimal length for the sample (determined to be 49mm, eliciting an active force of 1224.88mN ); any deviations from the optimal length decreased the active force significantly. Graphical representations of passive forces produced an exponential relationship between length and the associated force; yielding a maximum of 39.86mN at 57mm. Visualisation and measurement of sarcomere microstructure were conducted through laser diffraction of the sample stretched to optimal length of 49mm. Fringe spacing of 100mm at a laser situated at a distance of 500mm produced determined sarcomere lengths of 3.17μm. The observations and recorded values at …show more content…
Modulation of muscle length in the isolated sartorius muscle of Rhinella marina displayed a proportional relationship with the elicited contractile forces. Changes in muscle length are directly correlated to changes in sarcomere length; the length of the muscle dictates the amount of overlap in the sarcomere. It is documented that the ideal overlap of the myosin and actin filaments is at the ‘optimum resting length’ (Winter, 2010). At this distance, the maximum force of contraction from a maximal stimulus will be produced; with further modulations in length promoting an overall decrease in contractile
Abstract:
An isolated Sartorius muscle of Rhinella marina was repeatability stimulated with electrical impulses to induce isometric contraction. Contractile forces evoked were measured with a force transducer and the relationship between force and muscle length was investigated through the modulation of sample lengths from 80%-140% of the sample resting length. The data was plotted and the active force produced a characteristic plateau effect, which presented an optimal length for the sample (determined to be 49mm, eliciting an active force of 1224.88mN ); any deviations from the optimal length decreased the active force significantly. Graphical representations of passive forces produced an exponential relationship between length and the associated force; yielding a maximum of 39.86mN at 57mm. Visualisation and measurement of sarcomere microstructure were conducted through laser diffraction of the sample stretched to optimal length of 49mm. Fringe spacing of 100mm at a laser situated at a distance of 500mm produced determined sarcomere lengths of 3.17μm. The observations and recorded values at …show more content…
Modulation of muscle length in the isolated sartorius muscle of Rhinella marina displayed a proportional relationship with the elicited contractile forces. Changes in muscle length are directly correlated to changes in sarcomere length; the length of the muscle dictates the amount of overlap in the sarcomere. It is documented that the ideal overlap of the myosin and actin filaments is at the ‘optimum resting length’ (Winter, 2010). At this distance, the maximum force of contraction from a maximal stimulus will be produced; with further modulations in length promoting an overall decrease in contractile