excitation contraction coupling refers to Excitationcontract

Excitation-contraction coupling refers to a. the muscle fiber\'s depolarization. b. the relationship between length of the sarcomere and the tension generated. c. the sliding of thick and thin filaments past one another. d. the relationship between excitation at the sarcolemma and release of calcium ions from the sarcoplasmic reticulum.

Solution

The answer is (d),Excitation–contraction coupling is the process by which a muscular action potential in the muscle fiber causes the myofibrils to contract. In skeletal muscle, excitation–contraction coupling relies on a direct coupling between key proteins, the sarcoplasmic reticulum (SR) calcium release channel (identified as the ryanodine receptor, RyR) and voltage-gated L-type calcium channels (identified as dihydropyridine receptors, DHPRs). DHPRs are located on the sarcolemma (which includes the surface sarcolemma and the transverse tubules), while the RyRs reside across the SR membrane.