Muscles

Explains muscular contraction giving examples of various types of muscle cells, tissues, and fibers. Relates muscle movement to chemical control and type of tissue involved. States that muscles can only contract and so must be arranged in pairs as shown in the specialized fibers of the hydra, the earthworm, the arthropods, and in man's arm. Discusses how a nerve tells a muscle to contract and cites the role of acetylcholine in this reaction. Mentions an insect's poisons and war gases as effective in this connection. Compares chemically a tired and rested muscle. Shows through photomicrographs the various types of muscle tissue and diagrams the part of actin and myosin in muscle contraction. Illustrates how the electron microscope can be used to study the detailed structure of objects. Guest lecturer, Dr. Charles Brown, Howard University.