This document summarizes the key components of muscle tissue and muscle contraction. It discusses nerve impulses, motor units, neuromuscular junctions, and the sliding filament theory of muscle contraction. The main components that allow for contraction are described, including myosin, actin, tropomyosin, troponin, and the calcium release initiated by a nerve impulse that allows for crossbridge binding and sarcomere shortening. Regions of the sarcomere such as the Z-line, A-band, I-band, H-zone, and M-line are also outlined.