With Regard to Skeletal Muscle Contraction,which Event Comes Last

Question

With regard to skeletal muscle contraction,which event comes last?
A) Shortening of the sarcomere
B) Release of calcium from the sarcoplasmic reticulum
C) Activation of the NM receptors by ACh
D) Release of neurotransmitter (ACh) from the somatic motor neuron

Accepted Answer

Shortening of the sarcomere is the final step in the process of skeletal muscle contraction. This occurs as the myosin heads pull on the actin filaments, causing them to slide past each other and shortening the sarcomere. The release of calcium from the sarcoplasmic reticulum, activation of the NM receptors by ACh, and release of neurotransmitter (ACh) from the somatic motor neuron are all steps that occur earlier in the process of skeletal muscle contraction.