Question 1: Define the main function of the kidneys in maintaining water balance in the body.

Answer: The kidneys regulate water balance by filtering blood, removing excess water and waste, and adjusting urine concentration to maintain homeostasis.

Question 2: Explain how antidiuretic hormone (ADH) influences the amount of water reabsorbed in the kidneys.

Answer: ADH increases the permeability of the kidney's collecting ducts, allowing more water to be reabsorbed into the bloodstream, resulting in more concentrated urine.

Question 3: Describe what happens to urine concentration when a person is dehydrated.

Answer: Urine becomes more concentrated with higher levels of solutes, and volume decreases as the kidneys reabsorb more water to conserve it.

Question 4: A person consumes 2 liters of water in a day. Their kidneys reabsorb 98% of this water. How much water is excreted in the urine?

Answer: 0.04 liters (or 40 milliliters)

Question 5: Which hormone is primarily responsible for controlling water reabsorption in the kidneys?

Answer: Antidiuretic hormone (ADH)

Question 6: Fill in the blank: During overhydration, the body reduces the secretion of ______ to produce more dilute urine.

Answer: ADH

Question 7: Explain the mechanism by which the kidneys respond to dehydration to conserve water. Include the role of specific structures and hormones.

Answer: When dehydrated, the hypothalamus signals the posterior pituitary to release ADH. ADH increases the permeability of the collecting ducts in the kidneys, allowing more water to be reabsorbed into the bloodstream. This results in concentrated urine and helps conserve water, maintaining blood volume and pressure.

Question 8: Identify the variables that can affect the kidney's ability to concentrate urine in an experiment setting.

Answer: Variables include levels of hydration, presence of ADH, kidney health, and temperature conditions.

Question 9: Describe a real-world application of kidney water regulation knowledge in the medical or technological field.

Answer: Understanding kidney water regulation helps in developing treatments for dehydration, kidney diseases, and designing artificial kidneys or dialysis machines.

Question 10: What is the primary risk associated with long-term overhydration?

Answer: Long-term overhydration can lead to hyponatremia, a condition where sodium levels in the blood become dangerously low.

Question 11: Summarize how the kidneys contribute to maintaining homeostasis in relation to water balance.

Answer: The kidneys maintain water balance by filtering blood, reabsorbing water under the influence of hormones like ADH, and excreting urine with the appropriate concentration. They respond dynamically to the body's hydration status, ensuring stable blood volume, pressure, and electrolyte levels, which are essential for overall homeostasis.