ecrease in blood water potential/concentration and the pituitary gland releases more ADH B1\n- ADH increases the permeability of the kidney tubules (or collecting ducts) to water B1\n- More water is reabsorbed back into the blood B1\n- Urine produced has a lower / smaller volume B1\n- Urine produced is more highly concentrated B1","marks":5,"order":1,"markingRubric":null,"explanation":{"methods":[{"id":"adh_water_balance","label":"ADH water balance","steps":[{"type":"text","order":0,"title":"Identify the imbalance","content":"Sweating causes extra water to leave the body. This makes the blood have **too little water** (a lower water potential), so the body must conserve water rather than lose more in urine.\n\nThis gives the starting condition needed for the control response.","highlights":[{"text":"water loss through sweating increases significantly","location":"specification"}]},{"type":"text","order":2,"title":"Release more ADH","content":"The **hypothalamus** detects that the blood has too little water. It causes the **pituitary gland** to release more **ADH** (antidiuretic hormone) into the blood.\n\nState both named structures and the increased ADH release for the first marking point.","highlights":[{"text":"Explain how the kidneys maintain water balance","location":"specification"}]},{"type":"text","order":3,"title":"Change the kidney tubules","content":"ADH makes the kidney tubules, especially the collecting ducts, **more permeable to water**. Permeable means that water can pass through their walls more easily.\n\nThis specific effect of ADH earns the next marking point."},{"type":"text","order":4,"title":"Reabsorb more water","content":"Because the tubules are more permeable, more water moves from the kidney tubules back into the blood. This is called **reabsorption**.\n\nThe body therefore retains water, helping to return the blood water level towards normal. This is the third marking point."},{"type":"text","order":5,"title":"State both urine changes","content":"As more water is reabsorbed, less water remains in the kidney tubules to form urine. Therefore the urine has:\n\n- a **smaller volume**; and\n- a **higher concentration**.\n\nGive both effects explicitly: each earns one marking point.","highlights":[{"text":"state the effect on the concentration and volume of urine produced","location":"specification"}]}]}],"generatedAt":"2026-07-22T09:14:43.761Z","modelVersion":"gpt-5.6-terra+diagrams-1","explanationVersion":"v3"},"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null}],"subjectCode":"gcse_biology__ocr","summaries":[{"id":"03debfde-042e-4439-a6b0-eca0f67c2b7a","difficultyBand":"hard","calculatorUse":null},{"id":"05240730-24dc-40c3-aa9d-884d8da569f8","difficultyBand":"easy","calculatorUse":null},{"id":"079a2a8f-fc4e-4c58-9192-7baca820e83e","difficultyBand":"medium","calculatorUse":null},{"id":"0cfcb6f4-b58b-4126-b9f1-576442570c20","difficultyBand":"hard","calculatorUse":null},{"id":"10584537-49cd-4fa8-9843-fcc3e7b970ff","difficultyBand":"medium","calculatorUse":null},{"id":"136f3dbd-75d4-4682-a1bf-14aa3af1c3ba","difficultyBand":"medium","calculatorUse":null},{"id":"1aac7678-ec70-4017-a9e5-20ed4ef58a8e","difficultyBand":"easy","calculatorUse":null},{"id":"1b522717-e3dc-44aa-a4ba-22e61429d3c6","difficultyBand":"easy","calculatorUse":null},{"id":"21ff9571-18b7-456c-a537-6acb565fd19e","difficultyBand":"easy","calculatorUse":null},{"id":"22e38110-2008-4579-b2d6-69c09b4cceb1","difficultyBand":"medium","calculatorUse":null},{"id":"255936ab-b428-41dc-863a-f547d25cf17c","difficultyBand":"medium","calculatorUse":null},{"id":"28d20134-8866-4937-83fd-64ad26bc09f3","difficultyBand":"medium","calculatorUse":null},{"id":"2e7810d4-597f-4bad-94d1-be492a49acef","difficultyBand":"hard","calculatorUse":null},{"id":"30c4a4a5-a23d-4fda-b4d4-30a6f07fb7ec","difficultyBand":"medium","calculatorUse":null},{"id":"31c8d9cf-cfb9-4744-bef8-2feb1e6a76d6","difficultyBand":"hard","calculatorUse":null},{"id":"3719141e-3367-4de8-b97c-434351d4

Maintaining internal environments

Question 10

Maintaining internal environments Questions

Maintaining internal environments

Question 10

Maintaining internal environments Questions