ALU 301 A&P Chapter 7 The Muscular System Practice Questions and Answers

Organ systems involved in Movement Muscular- Moves the bones Skeletal- bones are moved at joints by muscles Nervous-transmits impulses to muscle to cause contraction Respiratory- Exchanges O2 and CO2 between the air and blood. Circulatory: transports O2 to muscles and removes CO2 Muscle Structure 1. Muscle fibers (cells) are specialized to connect, shorten and produce movement. 2. A skeletal muscle is made of thousands of muscle fibers. 3. Tendons attach muscles to bones Antagonistic muscles have opposite functions- A muscle pulls when it contracts but exerts no force when it relaxes and it cannot push. The frontal lobes of the cerebrum generate the impulses necessary for contraction of skeletal muscles. The cerebellum regulates coordination. Synergistic muscle have the same function and alternate as prime mover depending on the position of the bone to be moved. Synergist also stabilize a joint to make more precise movement possible. Muscle Tone The state of slight contraction present in muscles. Alternate fibers contract to prevent muscle fatigue regulated by the cerebellum. Good tone helps maintain posture, produces 25% of body heat and improves coordination. Isotonic exercise involvement contraction with movement, improves tone,strength, cardiovascular and respiratory efficiency. Concentric contraction muscle exerts force while shortening. Eccentric Contraction muscle exerts force while lengthening. Isometric exercise involves contraction without movement Energy Sources of Muscle Contraction ATP: the direct source stored in muscles last only a few seconds. Creatine phosphate: Secondary energy source broken down to creatine + phosphate + energy.