BIOLOGY 151 Lecture Notes - Lecture 39: Skeletal Muscle, Atp Hydrolysis, Sarcomere
Document Summary
How muscles work: can only contract. Never push: 2 main categories of antagonistic muscles. Those responsible for bringing about movement (contraction via pulling) Those responsible for reversing the movement (relaxation via letting go) Striations due to highly ordered arrangement of fibrous proteins. Way striations change during contractions lead to the explanation of the mechanisms underlying the contraction: voluntary muscle, structure. A muscle is composed of muscle fibers. Each muscle fiber is as long as the muscle itself: extends from one tendon to another, because of multinucleate nature, fibers formed by fusion of precursor cells. Each fiber contains bundles of myofibrils: made mostly of actin (thin filaments) and myosin (thick filaments) Symmetrical about center of symmetry in the middle of the filament. Each one made up of a collection of myosin molecules: they overlap, filament is longer than any one myosin. Tropomyosin and troponin are important in turning contractions on and off. Thick and thin fibrils slide past each other.
