The respiratory system is important because it provides oxygen to our body's cells. Without oxygen, we would not be able to survive. The digestive system is very important to all the other systems. It provides nutrients for the cells of all other systems in our body to work. The respiratory system is very important to the circulatory system.
Blood is pumped from the heart to the lungs.
The lungs oxygenate the blood, then the oxygenated blood is carried throughout the body. Our cells cannot function without oxygen.