Question 1: Define the term 'hormone'.

Answer: A chemical messenger produced by endocrine glands that travels through the bloodstream to target organs, regulating various physiological processes.

Question 2: Explain how the endocrine system helps maintain homeostasis in the body.

Answer: It releases hormones that regulate processes such as blood sugar levels, water balance, and temperature, ensuring the body's internal environment remains stable.

Question 3: Describe the mechanism by which the pancreas regulates blood glucose levels.

Answer: The pancreas secretes insulin when blood glucose is high, which promotes uptake of glucose by cells and storage as glycogen. When blood glucose is low, it releases glucagon to convert glycogen back into glucose, maintaining balance.

Question 1: If a person’s blood glucose level is measured at 8 mmol/L after a carbohydrate-rich meal, and the normal fasting level is 5 mmol/L, how much glucose needs to be removed to bring the level back to normal? Assume 1 mmol of glucose weighs approximately 180 mg. Calculate the total mass of glucose to be removed.

Answer: 900 mg

Question 2: A hormone is secreted at a rate of 0.5 units per minute. How much hormone is secreted in 2 hours? Express your answer in units.

Answer: 60 units

Question 1: Describe a basic experimental setup to test the effect of insulin on blood glucose levels in a laboratory setting.

Answer: Use a sample of blood or a simulated model, measure baseline glucose levels, then introduce insulin, and measure the glucose levels at intervals. Ensure proper safety precautions, such as wearing gloves and handling reagents carefully.

Question 2: Identify two variables that should be controlled in such an experiment and explain why.

Answer: Variables to control include temperature and pH, because they can affect hormone activity and the accuracy of the results.

Question 1: A patient’s blood tests show elevated levels of cortisol during stressful events. Explain the role of cortisol in response to stress and how it helps the body.

Answer: Cortisol helps increase blood sugar levels by promoting the breakdown of fats and proteins, providing energy needed to cope with stress. It also suppresses non-essential functions to prioritise immediate survival.

Question 1: Describe the process by which the thyroid gland regulates metabolic rate. Include the hormones involved and their effects.

Answer: The thyroid gland secretes thyroxine, which increases the metabolic rate by stimulating cells to produce more energy. It is regulated by the hypothalamus and pituitary gland through TSH (thyroid-stimulating hormone). When metabolism is low, the pituitary releases more TSH to stimulate thyroxine production.

Question 1: Explain how insulin therapy is used in the treatment of diabetes and discuss one potential challenge of this treatment.

Answer: Insulin therapy involves injecting insulin to regulate blood glucose levels in diabetics. A challenge is managing dosage accurately to avoid hypoglycemia or hyperglycemia.

Question 2: Discuss how advances in biotechnology, such as hormone replacement therapy, have improved management of endocrine disorders.

Answer: Biotechnology enables the production of synthetic hormones, allowing effective hormone replacement therapies for conditions like hypothyroidism or adrenal insufficiency, improving patients' quality of life and enabling better control of hormonal imbalances.