NEET BIOLOGY

Detailed explanation-1: -The sarcoplasmic reticulum in the muscle fibers resembles a network of smooth endoplasmic reticulums. This Sarcoplasmic reticulum functions as a storehouse of calcium iron. Calcium ions are important for the contraction and relaxation of muscles.

Detailed explanation-2: -Skeletal muscle stores Ca2+ in the sarcoplasmic reticulum (SR) and releases it to initiate contraction, but the concentration of luminal Ca2+ in the SR ([Ca2+]SR) and the amount that is released by physiological or pharmacological stimulation has been difficult to measure.

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: -This study provides direct evidence that Ca2+ release from the sarcoplasmic reticulum, either through ryanodine or inositol 1, 4, 5-trisphosphate (InsP3) receptors, increases both cytosolic and mitochondrial [Ca2+] in smooth muscle cells.

Detailed explanation-5: -The ryanodine receptor is the major Ca2+ release channel in skeletal and cardiac muscle and has been studied in far greater detail than other sarcoplasmic reticulum ion channel proteins.