Name all four substances filtered at the glomerulus
Connect water glucose urea and ions with blood-to-nephron filtration.
Exam scope and assessment notes
Extended only (Supplement) · Biology 0970, 2026–2028. Use the stated specimen features and evidence. Diagrams are schematic. Written practice is self-checked; human subject-teacher review, supervised practical competence and cumulative assessment remain pending. Cambridge states that IGCSE 0970 has the same subject content as IGCSE 0610, with 9–1 grading. This StudyForA pathway maps the 2026–2028 syllabus only. This 9–1 graded qualification is available only in a limited number of administrative zones. Confirm that your centre can enter you for this code and exam series with Cambridge International. Cambridge has published a separate syllabus for 2029. StudyForA has not reconciled that version yet; this page supports exams in 2026, 2027 and 2028 only.
Before you begin
- Recall cell metabolism, blood transport, amino acids and the distinction between excretion and egestion.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Which useful nutrient is included in the stated filtrate?
What you will learn
- Filtration includes useful and waste substances
- Keep the starting fluid distinct from final urine
Name all four substances filtered at the glomerulus
The required initial filtrate includes all four substances. Useful material can be filtered and later returned; blood, initial filtrate and final urine are different stages. Original teaching model.
| Feature | Meaning |
|---|---|
| Origin | Blood at the glomerulus |
| Filtered water | Water |
| Filtered solutes | Glucose · urea · ions |
| Later processing | Reabsorption changes the tubule contents |
Filtration includes useful and waste substances
The glomerulus filters water, glucose, urea and ions from blood into the nephron fluid in the required outline. State all four rather than saying only waste is filtered. Glucose and some water and ions can be useful substances, but their presence in the initial filtrate is compatible with later reabsorption.
The glomerulus is a capillary network, not a storage sac of pure urine. Blood is the source fluid for filtration, and the filtered fluid enters the nephron route. The process is followed by reabsorption and urine formation, so identifying a substance in the initial filtrate does not establish that the same amount will leave the body.
Keep the starting fluid distinct from final urine
The simplified school-level filtration account distinguishes the small named substances from blood cells and large blood proteins, which normally remain in blood rather than becoming the stated initial filtrate. Detailed filtration barriers and pressures are not required here. Do not state that whole unchanged blood is the normal urine mixture.
A comparison question may ask for a useful substance in the filtrate: glucose is an important example because the subsequent outline requires all filtered glucose to be reabsorbed under normal conditions. Answer the step requested. Describing glucose return at a later stage does not mean it was never filtered in the first place, and neither stage is a personal medical test.
Pause and explain
Which filtered list is complete?
Worked example
List the four substances filtered from blood in this outline.
Show the worked solution
- Include both water and dissolved substances.
- Useful glucose is included alongside urea and ions.
Answer Water, glucose, urea and ions.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
State the role of the glomerulus using all four required substances.
Give me a hint
Name origin, destination and cargo.
Compare my reasoning
- The source is blood.
- Water, glucose, urea and ions enter the nephron fluid through filtration.
The glomerulus filters water, glucose, urea and ions from blood into the nephron fluid.
Look for these in your work
- Name all four
- Give blood-to-nephron direction
A student says glucose cannot be filtered because it is useful. Correct the account.
Give me a hint
Filtration and later return are different steps.
Compare my reasoning
- Glucose is included in the required filtrate.
- It is then reabsorbed under the normal outline.
Glucose can be filtered from blood and then reabsorbed; usefulness does not mean it never enters the initial filtrate.
Look for these in your work
- Retain filtration
- Locate subsequent return
Does the initial presence of glucose in filtrate prove normal urine must contain the same amount?
Give me a hint
A later processing step changes the contents.
Compare my reasoning
- All filtered glucose is reabsorbed in the normal outline.
- Initial filtrate differs from final urine.
No; normal reabsorption returns all filtered glucose to blood in this outline, so the initial filtrate does not determine unchanged final urine.
Look for these in your work
- Separate stages
- State all-glucose return
Common mistakes
- Saying filtration includes only waste.
- Treating initial filtrate as unchanged final urine.
What can you explain now?
Which filtered list is complete?
Compare with the explanation
Water, glucose, urea and ions
All four required substances are named.
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Make it stick
List every filtered substance and explain why useful glucose is included.
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.