What are muscle fibers primarily composed of?

Muscle fibers are primarily composed of myofibrils, which are the structural units of a muscle cell. Myofibrils are composed of long chains of proteins called actin and myosin, which interact to facilitate muscle contraction. This unique structure allows muscle fibers to generate force and produce movement effectively. Each muscle fiber contains many myofibrils arranged parallel to each other, contributing to the muscle's ability to contract and relax.

While collagen is an important protein in connective tissues and provides support and strength to structures surrounding muscles, it is not a primary component of muscle fibers themselves. Elastic fibers contribute to the elasticity of tissues but do not play a role in the muscular contraction mechanism. Neurons are responsible for transmitting signals to muscles, but they are not part of the muscle fibers' composition. The focus on myofibrils highlights their crucial role in the functionality and performance of muscle tissue.