MUSCLE PHYSIOLOGY

Detailed explanation-1: -Cardiac sarcoplasmic reticulum (SR) serves as a Ca2+ reservoir for contraction, which reuptakes intracellular Ca2+ during relaxation. The SR Ca2+ reserve available for beats is determinate for cardiac contractibility, and the removal of intracellular Ca2+ is critical for cardiac diastolic function.

Detailed explanation-2: -Ca2+ ions trigger muscle contraction and the release of Ca2+ from the sarcoplasmic reticulum (the intracellular Ca2+ storage site) plays an important role in determining the intramuscular Ca2+ concentration.

Detailed explanation-3: -The sarcoplasmic reticulum (SR) is a membrane-bound structure found within muscle cells that is similar to the smooth endoplasmic reticulum in other cells. The main function of the SR is to store calcium ions (Ca2+).

Detailed explanation-4: -What is the reservoir for Ca2+ in the body? *The skeleton acts as a reservoir for calcium.

Detailed explanation-5: -The Ca2+-adenosine triphosphatase (ATPase) of skeletal muscle sarcoplasmic reticulum is a single protein species that pumps calcium ions at the expense of adenosine triphosphate (ATP). The reaction cycle includes phosphorylated intermediates which change the affinity and orientation of calcium sites.