Answer:
Membranous channel extending inward from muscle fiber membrane , is the transverse tubules.
Explanation:
Transverse tubules -
Transverse tubules also called the T - tubules , are basically the extensions of the cell membrane that penetrates into the center of the skeletal and the cardiac muscle cells .
T - Tubules are made up of phospholipid bilayer .
T - Tubules are directly connected to the sarcolemma at one of the end , forming a network of the tubules running parallel and perpendicular to the sarcolemma.
