Question

When stimulation voltage was increased above threshold, did the force of contraction increase, decrease, or stay the same? Explain why this occurred.

In my experiment, the force of contraction stayed the same

Answer 1

Ans- When stimulus voltage is increased above threshold, the force of contraction remains same. This is because it follows all of none law. When stimulus is given below a particular value that is threshold value, the muscle will not contract. But when the stimulus reaches the threshold value, the force of contraction increases and there is contraction in muscle. However on furthur increase of stimulus , there is no change in the force of contraction, it will remain same. A motor neuron is innervates many muscle fibres in skeletal muscles which is called motor unit. These act in coordinated fashion and one stimulus will affect all of the muscle fibres innervated by the given motor unit.