circulatory system

Your Respiratory and Circulatory Systems work together to bring in oxygen to your body. Together, they bring in the oxygen, take it to your muscles and organs, and remove waste from your body, which we call carbon dioxide. 

So your respiratory system is responsible for bringing the oxygen into your body. The circulatory system helps move the oxygen (in your blood) throughout your body.

So, oxygen and nutrients go into your body. The waste (bad stuff) goes out!!

Your body needs oxygen to work! When you breathe in air, it contains oxygen. The oxygen travels into your lungs.

Your lungs are surrounded by tiny blood vessels called capillaries. These blood vessels absorb (like a sponge) the oxygen and put it into your blood.

Blood that has oxygen enters your heart. When your heart beats, it pumps this blood into your body. As the oxygen-rich blood moves through your body it gives the oxygen to your muscles and organs. 

Your muscles and organs use the oxygen to do work and they create waste- carbon dioxide. 

When oxygen-poor (no oxygen) blood gets back to your heart, it sends this blood to your lungs. When you exhale, you breathe the carbon dioxide (waste/bad stuff) out, and the cycle is complete!