MEDICAL PHYSIOLOGY

Detailed explanation-1: -When the muscle is stimulated, calcium ions are released from its store inside the sarcoplasm ic reticulum, into the sarcoplasm (muscle ). Invaginations of the plasma membrane (sarcolemma) of the muscle fibres are called T (or transverse) tubules .

Detailed explanation-2: -In a muscle fibre, Ca++ is stored in the sarcoplasmic reticulum.

Detailed explanation-3: -The sarcoplasmic reticulum of a skeletal muscle fiber stores calcium ions, which are released to initiate muscle contraction. Now, we know the structure within skeletal muscles that stores and releases calcium ions needed to initiate muscle contractions. This organelle is called the sarcoplasmic reticulum.

Detailed explanation-4: -Depolarization of the sarcolemma (muscle membrane) caused by nerve stimulation causes calcium ions to be released from the sarcoplasmic reticulum.

Detailed explanation-5: -The sarcoplasmic reticulum releases calcium ions during muscle contraction and absorb them during relaxation.