1. A football player worked out for 3 hours. He drank some water, but his heart rate was abnormal. What caused his abnormal heart rate? 2. T.S. suffers from bulimia which can lead to hypokalemia (low potassium) due to excessive vomiting. One day, T.S. was found unresponsive and was brought to the ER with cardiac arrest. What caused T.S.'s cardiac arrest? 3. Pheochromocytoma (tumor in the adrenal medulla) can cause sinus tachycardia (rapid heart rate) and hypertension. What causes the tachycardia? 4. G.K. had unexplained weight gain, fatigue, and was sensitive to cold. She was diagnosed with Hashimoto's thyroiditis. Does G.K. have hyper- or hypothyroidism? Would she experience bradycardia or tachycardia? How would her condition affect metabolism? 5. Ca2+-channel blockers are a common medication used to treat high blood pressure. How would these drugs affect heart rate and contractility?