Each physical or health hazard is a âhazard classâ (e.g., Carcinogenicity is a hazard class). A âhazard classâ may be sub-divided in the criteria into. several âhazard categoriesâ based on the degree of. severity of the hazard.
Quick Answer. Calcium is a crucial part of muscle contraction. The ionic element is released from muscles during contraction and relaxation. The release of calcium helps propagate the muscle contraction and relaxation stages. Continue Reading.
Calcium ions (Ca2+) link action potentials in a muscle fiber to contraction. 1  In resting muscle fibers, Ca2+ is stored in the endoplasmic (sarcoplasmic) reticulum. 2  Spaced along the plasma membrane (sarcolemma) of the muscle fiber are inpocketings of the membrane that form T-tubules.