MICROANATOMY

Detailed explanation-1: -As mentioned earlier, the plasma membrane of a skeletal muscle fiber is called the sarcolemma. The sarcolemma invaginates into the cytoplasm of the muscle cell (sarcoplasm). This forms membranous tubules that pass across the muscle cells. These are called transverse tubules (or ‘T tubules’).

Detailed explanation-2: -The sarcolemma is also called the myolemma and is the cell membrane of a striated muscle fiber cell. The function of the sarcolemma is same as that of the plasma membrane of the eukaryotic cells. Thus, the correct answer is option (B), ‘Muscle fibres’.

Detailed explanation-3: -The sarcolemma (sarco (from sarx) from Greek; flesh, and lemma from Greek; sheath) also called the myolemma, is the cell membrane surrounding a skeletal muscle fiber or a cardiomyocyte. It consists of a lipid bilayer and a thin outer coat of polysaccharide material (glycocalyx) that contacts the basement membrane.

Detailed explanation-4: -The sarcolemma maintains the intracellular milieu, actively transports substrates into the muscle cell, serves as a docking location for proteins originating in the basement membrane and cytoskeleton, and also transmits neural excitatory impulses that lead to muscle contraction.

Detailed explanation-5: -The plasma membrane of differentiated skeletal muscle fibers comprises the sarcolemma, the transverse (T) tubule network, and the neuromuscular and muscle-tendon junctions.