Which triggers the release of calcium ions from: sarcoplasmic reticulum?
Correct answer: B. An action potential
- A. Formation of actin-myosin cross bridges
- B. An action potential
- C. Sarcomere contraction
- D. An increase in calcium ion concentration
Explanation
An action potential, which is an electrical signal generated by nerve cells, triggers the release of calcium ions from the sarcoplasmic reticulum. The action potential travels along the sarcolemma (muscle cell membrane) and down the T-tubules, leading to the activation of calcium-release channels in the sarcoplasmic reticulum called ryanodine receptors (RYR). These channels open, allowing calcium ions to flow from the sarcoplasmic reticulum into the cytoplasm of the muscle cell.
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About Support and Movement
Support and movement covers the axial and appendicular skeleton, bone structure, joints and the arrangement of skeletal muscles. Muscle contraction is explained through actin, myosin, sliding filaments, calcium ions and ATP, while arthritis is distinguished as a disorder of joints rather than a normal part of movement.
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