Contents
Key Stage 3
Meaning
A drawing of a kidney.
Kidneys are organs in the excretory system that removes urea and excess water from the blood.
About the Kidneys
- The kidneys are linked to the bladder by ureters.
- The kidneys filter the blood to remove some toxic substances.
Key Stage 4
Meaning
Kidneys are organs in the excretory system that removes urea and excess water from the blood.
About the Kidneys
- The kidneys are responsible for osmoregulation.
- As blood passes through the kidneys water, urea, glucose and salts diffuse into the kidney tubules. Glucose is completely reabsorbed into the blood while water is selectively reabsorbed depending on the water concentration in the blood.
- The selective re-absorption of water is affected by anti-diuretic hormone. When the levels of anti-diuretic hormone are high most of the water is reabsorbed into the blood. When the levels of anti-diuretic hormone are low the water is not re-absorbed and is passed down the ureters to the bladder.