1. Which hormone is primarily responsible for the regulation of blood glucose levels? A. Insulin B. Glucagon C. Cortisol D. Epinephrine Answer: A. Insulin Rationale: Insulin, produced by the pancreas, is the hormone responsible for lowering blood glucose levels by facilitating the uptake of glucose into the cells. 2. What is the role of the parathyroid hormone (PTH) in calcium homeostasis? A. Decreases blood calcium levels B. Increases blood calcium levels C. Has no effect on calcium levels D. Decreases calcium absorption in the gut Answer: B. Increases blood calcium levels Rationale: PTH is secreted by the parathyroid glands and acts to increase blood calcium levels by stimulating bone resorption, increasing intestinal calcium absorption, and promoting calcium reabsorption in the kidneys. 3. A patient with Addison's disease would exhibit which of the following laboratory findings? A. High blood glucose levels B. Low serum cortisol levels C. Elevated TSH levels D. Increased blood pressure Answer: B. Low serum cortisol levels Rationale: Addison's disease is characterized by inadequate production of cortisol and aldosterone by the adrenal glands, leading to low serum cortisol levels. 4. Which of the following is a symptom of hyperthyroidism? A. Bradycardia B. Weight gain C. Cold intolerance D. Heat intolerance