The basic fibrous element of muscles. Fetal muscle is composed of about 90% water, with the adult water content of about 76% being reached by 7 months after birth, together with a large increase in protein, total lipids and triglycerides (a form of fat circulating in the blood). Subsequently, little change occurs in the relative percentages of muscle constituents until old age when they begin to decrease.
See Actin, Appendicular muscles, Axial muscles, Electromyography, Extrafusal muscle fibers, Fasciculation, Firillation, Golgi tendon organ, Intrafusal muscle fibers, Isotonic contraction, Lipids, Motoneuron, Motor end plate, Motor cortex, Musculoskeletal system, Myofilament, Myoblast, Myofibrils and myofilaments, Myosin, Neuromuscular junction, Polyneural to mononeural innervation, Proteins, Striated (or striped or voluntary) muscle, Type 1 muscle fibers, Type 2 muscle fibers