Question

Skeletal muscle fiber is “Syncytium” which means it is?
A. Made up of many fibers
B. Made up of many proteins
C. Long and slender
D. Swollen in the middle with tapered ends
E. Multinucleated

Answer 1

Hint: In our body, one of the main functions of syncytium is as part of the skeletal muscle. Skeletal muscles are sometimes called the voluntary muscles, and they include muscles which are directly attached to the skeleton that can be moved consciously. Skeletal muscles are made up of many individual muscle fibers, twined together to provide flexibility and strength. These muscle fibers are individual, long syncytia.

Complete answer:
Skeletal muscle cells, more commonly known as muscle fibers, are multinucleated syncytia formed during development by the fusion of mononucleated precursor cells called the myoblasts. They measure 10–100 micrometers in diameter and may have lengths from a few millimeters up to almost a meter. Close to plasma membrane, hundreds of nuclei are located in cell periphery, whereas most of the cytoplasm is occupied by longitudinally arrayed myofibrils composed of myofilaments: thick filaments assembled from the myosin II molecules consisting rod-shaped segments and globular heads projecting out of filaments, and thin filaments made up of actin.
One advantage of syncytia is fast response and communication between the muscles and the brain. The lack of separate membranes allows impulses from the brain to quickly move between the nuclei. The faster the impulses move, the faster our muscles can react.

Hence, the correct answer is option (E).

Note: Syncytia can be found in pregnant women. The formation of a syncytium happens very early during the development process, when the baby is still in the embryo stage. In humans, embryo stage starts about four days after the fertilization of the egg and continues through the eighth week of pregnancy.