The Muscular System

1. The Muscular System

2. 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

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

4. Production of Movement Origin Innervation 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

5. 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