Digestive system
Food that we eat is digested by our digestive system. The nutrients from the food are absorbed into the blood vessels of our circulatory system.
Circulatory system
Our circulatory system carries the nutrients from teh digested food to the different parts of our body.
It also carries blood with waste substances to our kidneys, and carries clean blood to the different parts of our body.
Urinary system
Our kidneys remove the waste substances from our blood. This clean blood then enters the circulatory system again.
The waste substances that have been filtered by our kidneys leave our body as urine through the urethra.