A detailed lesson on how the kidneys work. It explains excretion of urea, filtration at the glomerulus and Bowman’s capsule, reabsorption in the nephron and control of water concentration, with key words and thinking questions throughout.
What this presentation covers
- urea and excretion
- the renal artery, renal vein and ureter
- the nephron
- filtration at the glomerulus and Bowman’s capsule
- reabsorption of glucose, water and salts
- control of water concentration
- key words and review questions
Level: GCSE
Slides: 16
Format: PowerPoint (.pptx)
Teaching notes
How to use it. A detailed 16 slide lesson for GCSE Biology (Homeostasis and response, separate science in AQA). The thinking questions built into the slides make good pause points. A diagram of the nephron for pupils to annotate as you go, marking where filtration and reabsorption happen, turns it into an active lesson, and a kidney dissection makes a memorable follow up.
Key words
- Urea: a waste product made in the liver when excess amino acids are broken down
- Nephron: one of about a million tiny filtering units in each kidney
- Glomerulus: a knot of capillaries where the blood is filtered under high pressure
- Bowman’s capsule: the cup around the glomerulus that collects the filtered liquid
- Selective reabsorption: taking back useful substances, such as all the glucose, into the blood
Common misconception: “The kidneys only filter out what the body does not need.” Filtration is not selective. Small molecules, including glucose, water, salts and urea, are all filtered out first. The kidney then reabsorbs what the body needs and lets the rest leave as urine.
Quick check questions
- Where is urea made?
- Why is there no glucose in the urine of a healthy person?
- Which blood vessel carries blood to the kidney?
Show answers
- In the liver.
- All the glucose is reabsorbed back into the blood in the nephron.
- The renal artery.
Related lessons: Homeostasis | Diffusion and Osmosis | Blood
New free lessons every week.Follow World of Teaching on Facebook so you never miss one.Follow on Facebook