What are the filaments that make up muscle fibers known as?

The filaments that make up muscle fibers are known as myofibrils. Myofibrils are long, cylindrical structures that run the length of muscle fibers and are composed of smaller subunits, known as sarcomeres, which are the basic functional units of muscle contraction. Each sarcomere contains the appropriate arrangement of thick and thin filaments—primarily myosin and actin, respectively—necessary for muscle contraction.

In the context of muscle structure, myofibrils play a crucial role in the overall function of muscle tissue, translating biochemical signals into mechanical action. As the muscle contracts, these myofibrils shorten by the sliding filament mechanism, involving the interaction between actin and myosin filaments. Understanding the organization of myofibrils and their components is essential for studying muscle physiology and performance in equestrian sports.