Question

Sarcolemma is the covering of
A. Nerve fibres
B. Muscle fibres
C. Bone marrow
D. Liver, kidney and stomach

Answer 1

The sarcolemma is the thin, transparent, extensible plasma membrane of the muscle cell. The sarcolemma contains the cell membrane and an outer coat made up of a thin polysaccharide material with many of the thin collagen fibrils.

Complete answer: The sarcolemma is the cell membrane of the striated muscle fibre cell. It is also known as the myolemma. The function of the sarcolemma is similar to the function of the plasma membrane of eukaryotic cells. The plasma membrane covering the muscle fibre is known as the sarcolemma. The anatomy of the sarcolemma is similar to the plasma membrane. The muscle cells are also called muscle fibres due to their long and cylindrical shape. The sarcolemma is reported to have two layers. The first layer is the plasma membrane, which is a structure of the similar biochemical composition to the general plasma membrane can be seen in the eukaryotic cells. The next layer is the glycocalyx, which is in contact with the basement membrane. The basement membrane is very rich in the collagen fibrils and the proteins that allow the muscle fibres to stick to it. The cytoskeleton of the muscle cell, which contains a great amount of the protein actin, also connects to the basement membrane through the transmembrane proteins present in the plasma membrane. The ends of the muscle fibres combine with tendon fibres, which in turn collect into bundles to form muscle tendons. This attaches the muscle fibres to the bone.
Therefore, the correct answer is option B.

Note: The sarcolemma can electrically lead to the activation of muscle fibres by signals coming from the motor nerves. The sarcolemma contains ion-conducting pathways and channels from which elements like sodium, potassium, calcium, and chloride flow selectively and non-selectively.