Your kidneys filter your entire blood supply dozens of times a day, removing waste while keeping what your body needs.
The kidneys are the main organs of excretion, filtering blood to remove urea and other waste products, which leave the body as urine.
What waste product do the kidneys primarily remove from the blood?
Urea
The nephron is the functional unit of the kidney. Urine is formed through three steps: filtration (removing waste and small molecules from blood), reabsorption (returning useful substances like glucose and water to the blood), and secretion (adding extra waste directly into the urine).
What is the functional unit of the kidney called?
The nephron
Why is reabsorption an essential step in urine formation, not just filtration?
Because filtration alone would remove useful substances like glucose and most water along with the waste, so reabsorption returns these useful substances to the blood before urine is finalised
1. What are the main organs of excretion in humans?
2. What waste product do the kidneys mainly remove from the blood?
3. What is the functional unit of the kidney called?
4. Name the three steps involved in urine formation.
5. What useful substances are reabsorbed back into the blood during urine formation?
6. Where in the body is urea produced?
7. What tube carries urine from the kidney to the bladder?
8. Why would it be dangerous if urea built up in the blood instead of being excreted?
9. What organ stores urine before it leaves the body?
10. Why do the kidneys need to filter blood continuously rather than just occasionally?