Question 1: Define the term 'osmoregulation' as it relates to the function of the kidneys.

Answer: Osmoregulation is the process by which the kidneys control the concentration of water and solutes in the blood to maintain a constant internal environment.

Question 2: Explain how antidiuretic hormone (ADH) influences water reabsorption in the nephrons.

Answer: ADH increases the permeability of the collecting ducts in the nephrons, allowing more water to be reabsorbed back into the bloodstream, thus concentrating the urine.

Question 3: Describe the process of filtration in the kidneys.

Answer: Filtration occurs in the Bowman's capsule, where blood plasma is filtered from the glomerulus into the nephron, removing waste products and small molecules while retaining blood cells and large proteins.

Question 4: Calculate the concentration of urine if a person excretes 1.5 litres of urine containing 3 grams of dissolved solutes in 24 hours. Express your answer in grams per litre.

Answer: Concentration = total solutes (g) / volume of urine (L) = 3 g / 1.5 L = 2 g/L

Question 5: Identify which hormone is primarily responsible for regulating water reabsorption in the kidneys.

Answer: Antidiuretic hormone (ADH)

Question 6: Fill in the blank: The loop of Henle creates a concentration gradient in the kidney's medulla, which is essential for the process of __________ of urine.

Answer: concentration

Question 7: Describe a practical experiment to investigate the effect of different levels of ADH on water reabsorption in the kidneys. Include the variables and safety precautions involved.

Answer: Students could use kidney tissue samples or simulated models exposed to varying concentrations of ADH. The independent variable is the level of ADH, the dependent variable is the amount of water reabsorbed, and the controlled variables include temperature and pH. Safety precautions include handling biological materials with gloves and disposing of waste properly.

Question 8: In a scenario where a person drinks a large amount of water in a short period, explain how the kidneys respond to maintain water balance.

Answer: The kidneys respond by decreasing ADH secretion, resulting in less water reabsorbed, producing dilute urine to excrete excess water and restore balance.

Question 9: Data shows that a patient's urine osmolality decreased from 800 mOsm/kg to 300 mOsm/kg after drinking water. What does this indicate about their kidney function?

Answer: It indicates that the kidneys are effectively reducing water reabsorption to produce more dilute urine, which is a normal response to excess water intake.

Question 10: Explain how the kidneys contribute to maintaining blood pressure and volume.

Answer: The kidneys regulate blood pressure and volume by controlling the amount of water and salt reabsorbed. They release renin, which helps regulate blood pressure, and adjust water reabsorption via ADH, influencing blood volume and pressure.

Question 11: State a real-world application of kidney function knowledge in medical treatment or technology.

Answer: Understanding kidney function is essential for developing treatments for kidney diseases, such as dialysis, which replaces lost kidney function in patients with renal failure.