Kidneys make urine by taking waste products and other unwantedsubstances out of your blood
Substances are filtered out of the blood as it passes through the kidneys, this is called filtration
Useful substances including all the glucose some ions and the right amount of water are then absorbed back into the blood, this is called selectivereabsorption
Substances that are removed from the body in urine include urea and excessions and water
What is selective reabsorption?
Useful substances such as all the glucosesomeions and the right amount of water are absorbed back into the blood
What is urea?
A waste product from the breakdown of proteins
How do we lose water?
From the skin in sweat and from the lungs when we exhale (breathe out)
Examples
On a cold day if you don't sweat you'll produce moreurine which will be more pale and dilute
On a hot day you sweat a lot and you'll produce lessurine which will be darkcoloured and concentrated
Where does filtration and selective reabsorption take place?
