Question

WHAT ARE T-TUBULES IN MUSCLE? WHAT ARE IT'S FUNCTIONS?

IS IT LOCATED IN A MYOFIBRILOR A MUSCLE FIBRE?

Answer 1

Each muscle fibre is an elongated cell and its membrane is called sarcolemma. The sarcolemma is invaginated to form T-tubules (transverse tubules). T-tubules are extensions of the sarcolemma that open to outside of the fibre. Its cytoplasm is called sarcoplasm that contains numerous mitochondria called sarcosomes. The sarcoplasm also has an extensive endoplasmic reticulum termed as sarcoplasmic reticulum. A triad consists of T-tubule and the segment of sarcoplasmic reticulum on either side.