NSCA CSCS EXAM REVIEW

Which of the following substances regulates muscle actions? potassium calcium troponin tropomyosin - Answer- calcium Which of the following substances acts at the NMJ to excite the muscle fibers of a motor unit? acetylcholine ATP creatine phosphate serotonin - Answer- acetylcholine When throwing a baseball, an athlete's arm is rapidly stretched just before throwing the ball. Which of the following structures detects and responds to that stretch by reflexively increasing muscle activity? golgi tendon organ muscle spindle extrafusal muscle pacinian corpuscle - Answer- muscle spindle From which of the following is the heart's electrical impulse normally initiated? AV node SA node the brain the sympathetic nervous system - Answer- SA node Which of the following occurs during the QRS complex of a typical ECG? 1. depolarization of the atrium 2. repolarization of the atrium 3. repolarization of the ventricle 4. depolarization of the ventricle a. 1 and 3 only b. 2 and 4 only c. 1, 2, and 3 only d. 2, 3, and 4 only - Answer- b. 2 and 4 only Which of the following is the definition of power? m