Write a short note (2–3 sentences) on how the hormone antidiuretic hormone (ADH) helps the body conserve water.
Answer
ADH is released from the posterior pituitary when plasma osmolarity is high; it makes the distal convoluted tubules and collecting ducts of the kidneys more permeable to water, leading to increased water re‑absorption and the production of concentrated urine, thereby conserving water in the body.
Step-by-step solution
- State where ADH is produced and stored – the hypothalamus and posterior pituitary.
- Explain the stimulus for its release – increase in plasma osmolarity or decrease in blood volume.
- Describe its action on the kidneys – it increases water permeability of the distal tubules and collecting ducts.
- Conclude that more water is re‑absorbed, urine becomes concentrated, and water loss is reduced.
Common mistake: Thinking ADH acts directly on blood vessels to reduce water loss instead of acting on kidney tubules.
Concept tested: Hormonal regulation of water balance
Published · How this solution was prepared and checked
Related questions
- 1 Which hormone lowers the blood glucose level by promoting the uptake of glucose into body cells?
- 2 Which gland secretes the hormone thyroxine (T4) that controls the metabolic rate?
- 3 Which organ in the human body secretes the hormone insulin?
- 4 Which gland secretes the hormone glucagon that raises blood glucose level?
- 5 A hormone raises the blood calcium level from 7.5 mg/dl to 10.5 mg/dl in 12 minutes. What is the average rate of increase of calcium concentration per minute?
- 6 Rohit’s resting heart rate is 90 beats per minute. How many heartbeats will his heart make in 12 minutes?