Myofibrils are microscopic fibers that make up muscle cells and are responsible for muscle contraction. There are several synonyms for this term, including muscle fibers, muscular filaments, and sarcomeres. Each of these terms describes the same basic structural unit of muscle tissue, but they may be used in different contexts or with slightly different connotations. For example, the term "sarcomere" is often used in reference to the arrangement of myofibrils within a muscle cell, while "muscle fiber" may be used more broadly to refer to the entire muscle cell itself. Regardless of the specific synonym used, understanding the structure and function of myofibrils is essential in the study of human anatomy and physiology.