why does the maximum contractile force generated by heart increase with preload?

why does the maximum contractile force generated by heart increase with preload?

Expert Solution

maximum contractile force generated by the heart will increase with preload

This can be explained by the frank-starling law

preload of the heart is related with ventricular filling. when the blood fills up the ventricle it result in the stretching of cardiomyocyte present in the ventricles.

stretching of the cardiomyocyte is the increase in the length of the muscle fibe. when the length of the sarcomere is increased, it causes an increase in the tension created in the muscle cell, this called the muscle contraction.

The increase in the muscle contraction occurs due to change in the overlap of actin and myosin filament. the maximum contraction occurs at a optimum length (preload).The increase increase in muscle contraction is due to the increases sensitivity of the calcium ions towards the troponin.This result in the increased formation of actin myosin cross bridge. so more amount of calcium is released from the sarcoplasmic reticulum.Also there is decreasei n spacing of the actin and myosin filaments. Hence the muscle contraction is increased.

Sydney Mullin answered 2 years ago

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