Hphy 322 Final (A+ Graded)

CQ: During cross-bridge cycling, the energy released from ATP dephosphorylation is used for specific process? a. the power stroke, or pulling together of the actin filaments when myosin is bound to actin b. the release of the myosin head from actin c. the cocking back of the myosin head when it is not bound to actin d. holding the myosin head in a tight binding position to actin correct answers c. the cocking back of the myosin head when it is not bound to actin CQ: which of the following will occur when the Gi protein is activated? a. increased activity PDE b. increased activity adenylate cyclase c. decreased activity adenylate cyclase d. both A and B e. both A and C correct answers c. decreased activity adenylate cyclase define isokinetic contraction correct answers near constant velocity, variable length and tension define CONCENTRIC isotonic contraction correct answers strength of actin-myosin binding exceeds load (sarcomeres can shorten) -muscle shortening -decreasing joint angle -moving against force of gravity define ECCENTRIC isotonic contraction correct answers strength of actin-myosin binding does not exceed load (sarcomeres are lengthening) what -muscle lengthening -increase in joint angle -moving with force of gravity define MAXIMAL isometric contraction correct answers strength of actin-myosin cross-bridges does not exceed load, therefore no movement ex. pushing as hard as you can up against a wall define SUBMAXIMAL isometric contraction correct answers agonist and antagonist muscles both contract to maintain joint position, therefore not joint movement ex. squatting with NO movement what happens when ATP and Ca2+ are present in a muscle cell? correct answers continuous cross bridge cycling what determines load that can be opposed in contraction? correct answers number of cross bridges formed