The Muscular System

Important Terms for Muscle Movement Origin point of attachment to the more stationary bone Insertion point of attachment to the more movable bone Nerve innervation what nerve “ talks ” to the muscles to cause contraction or relaxation Action coordinated response of a group of muscles to bring body into movement TREND: When a muscle contracts, it shortens. This shortening causes the muscle ’ s insertion to move toward the origin … movement

Muscles for Practice Biceps brachii Origin Insertion Nerve Innervation Action Use 3 references to complete the chart: Wingerd pgs. 213, 223 BRB pg. 366 Musculoskeletal Anatomy pgs. 5, 7, 25, 75

Production of Movement OriginInnervation Insertion Action Prime mover (agonist) muscle that causes a desired action Antagonist muscle that relaxes & yields to the prime mover Synergist muscle that works with prime mover … steadying the movement by stabilizing the joint & moving bones Fixator muscle that stabilizes the bone & joint at the muscle ’ s origin

Types of Muscle Contraction Isotonic contraction –Produces movement as the muscle pulls on the bone –Consistent load through a range of motion –2 types Concentric (+) –Muscle shortens & pulls on bone to produce movement –Decreases joint angle Eccentric (-) –Muscle length increases during contraction to produce movement Isometric contraction –Produces muscle tension but muscle does not shorten –Same length