Core 4 1st mile - Study guides, Class notes & Summaries

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 a...