Osmoregulation and the Action of ADH · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

How ADH tunes your urine

Science · The Human Body · ages 17-18
Name ______________________   Date ____________

  1. Which part of the kidney does ADH act on?

    • The glomerulus filter
    • The loop of Henle pump
    • The collecting duct wall

  2. What does ADH stand for, and what is its job?

    • Antidiuretic hormone, cutting urine volume down
    • Adrenal duct hormone, widening the tubule
    • Active diffusion hormone, speeding filtration up

  3. When ADH levels rise, urine becomes more concentrated.

    Circle one:   True   False

  4. You drink a litre of water quickly. What does your urine do?

    • It turns small and dark within minutes
    • It stops completely until evening
    • It grows large in volume, pale and dilute

  5. After a salty meal, blood water potential falls. What follows?

    • Less ADH, so a flood of dilute urine
    • More ADH, so a small volume of concentrated urine
    • No ADH change, since salt is ignored

  6. What change does ADH make at the duct wall?

    • It makes the wall more permeable to water
    • It makes the wall fully waterproof forever
    • It dissolves the wall so filtrate escapes

  7. Why is ADH control an example of negative feedback?

    • It spends ATP to move water uphill
    • Its response reverses the blood change that triggered it
    • It keeps ADH levels permanently high

  8. A student says ADH makes the whole kidney filter more blood. What is wrong?

    • ADH only changes collecting duct permeability to water
    • ADH has no effect anywhere in the body
    • ADH blocks all urine formation completely
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Answer key

For grown-ups. Fold this page away before handing over the rest.

How ADH tunes your urine W1-mt_Rz_MmL-Pa--s1

  1. The collecting duct wall · ADH targets one wall: it changes the permeability of the collecting duct.
  2. Antidiuretic hormone, cutting urine volume down · Antidiuretic means against making lots of urine, which is what ADH does.
  3. True · More water leaves the tubule for the blood, so what remains is concentrated.
  4. It grows large in volume, pale and dilute · Dilute blood cuts ADH release, so water stays in the tubule and urine volume rises.
  5. More ADH, so a small volume of concentrated urine · Concentrated blood triggers ADH, which rescues water and concentrates the urine.
  6. It makes the wall more permeable to water · ADH adjusts permeability, letting more water pass back into the blood.
  7. Its response reverses the blood change that triggered it · Lost water triggers rescue, dilution triggers release, and each response restores normal.
  8. ADH only changes collecting duct permeability to water · Filtration runs on pressure at the glomerulus. ADH tunes water return at the duct.
Worksheet · LightMySky