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Year 11 - Science

Controlling water balance: the kidneys, nephron structure and kidney failure

Coordination and control: maintaining a constant internal environment

Unit Summary

This unit covers the importance of maintaining a constant internal environment, focusing on body temperature control, osmotic balance, and kidney function. It explains the roles of the skin, kidneys, and ADH, and emphasises data extraction, experiment techniques, and accurate data interpretation.

Lesson Summary

You will learn to describe the role of the kidneys in filtering the blood to control the water balance of the human body, the structure of a nephron, and treatments for kidney failure.

Key Notes

  • The kidneys are organs of the excretory system in the human body.
  • Blood passes through the kidneys and is filtered.
  • Urea and excess water and ions move out of the blood plasma into the kidney tubules and are excreted as urine.
  • The kidneys reabsorb as much water as needed from the urine into the blood plasma to maintain water balance in the body.
  • Having too much water in the body leads to dilute urine, and vice versa.

Vocabulary To Learn

  • urea: a waste product created in the process of breaking down excess amino acids
  • blood plasma: the liquid part of the blood which contains dissolved nutrients and waste products
  • kidney: the organ in the excretory system which filters waste products from blood plasma and controls water balance
  • excretory system: the organ system responsible for removing waste from blood plasma
  • urine: a combination of urea, and excess water and ions which is stored in the bladder until urinated

Common Mistakes To Avoid

  • Misconceptions about the roles of the kidneys, bladder and how the blood is 'cleaned' exist. Students often conflate/confuse these roles, muddle key terms or offer weak descriptions or explanations.

3 Quick Questions (With Answers)

1. Explain the scientific idea in this lesson using two key points.

The kidneys are organs of the excretory system in the human body. Blood passes through the kidneys and is filtered.

2. Define this scientific word and use it in context. 'urea'

a waste product created in the process of breaking down excess amino acids. Include the word in a full scientific explanation, not as a single label.

3. Correct this common scientific misunderstanding.

Mistake: Misconceptions about the roles of the kidneys, bladder and how the blood is 'cleaned' exist. Students often conflate/confuse these roles, muddle key terms or offer weak descriptions or explanations. Correction: The roles of the kidney and nephron are clearly described, and diagrams and flowcharts are used to support the detailed explanations. Tasks that reinforce understanding and check for clarity and correct use of key words are included too.

More Lessons In This Unit

Browse all guides in the Year 11 Science guide library.