BIOL 235: Chapter 11 (100% correct answers)

Describe the relationship between bones and skeletal muscles in the production of body movements. correct answers skeletal muscle is attached to bone at origin and insertion. skeletal muscle contracts and pulls on bone. bones serve as levers. joint act as a fulcrum. load is the weight of the object. Describe how the prime mover, antagonist, synergist and fixator in a muscle group work together to produce movements. correct answers Opposing pairs of muscle group, often on opposite side of the body, balance out movement. The agonist and antagonist change roles depending on the movement. If they contract equally then there is stability and no movement. The agonist will initiate a contraction and the antagonist will yield and stretch to that effect. Fixaor stabilze the origin. Synergists support the needs of the prime mover by stabilizing intermediate joints. . describe the characteristics used in the naming of skeletal muscles. correct answers combination of word roots of distinctive features. - direction of muscle fascicles (rectus are parallel to midline; transverse are perpendicular to midline; oblique are diagonal to midline) -size (major/ minor or short/long) -shape (deltoid =triangular; trapezius = trapezoid) -action (flexor - decrease joint angle; extensor - increase joint angle) - number of origins (biceps = two origins) list the names, locations and actions of principal skeletal muscles. correct answers ... list the origins and insertions of several specific skeletal muscles. correct answers ... origin correct answers attachment of muscle's tendon onto the stationary bone. usually proximal. insertion correct answers attachment of the muscles tendon to the moveable bone. usual distal. belly (body) correct answers fleshy part of the tendons between the tendons lever system and leverage (fulcrum, effort, load/resistance) correct answers levers - bones (rigid structure that moves around a fixed point (fulcrum) and i acted on by two opposing forces: load and effort fulcrum - joint load/resistance - weight of object + bone holding it effort - of the muscle that needs to contact prime mover or agonist correct answers within opposing pairs of skeletal muscles, this one leads the contraction to cause an action antagonist correct answers within opposing pair of skeletal muscles, this one yields and stretches to the force of the prime mover (agonist)