READ: Cardiovascular and Respiratory Systems

The above image shows the tissue found inside of the lungs. The lungs contain alveoli. Alveoli absorb oxygen and send it to the blood vessels. They also move carbon dioxide from the blood vessels back to the lungs to be exhaled.

Alveoli look like clumps of grapes. Why do you think it is important that your body have many alveoli? What would happen if your alveoli lost their ability to function? Why do you think alveoli are shaped like spheres?

The respiratory system is important because it brings oxygen to cells in your body. But it also removes a waste, carbon dioxide. Another system in your body, the excretory system, also removes wastes. The excretory system moves waste from your digestive system and from your blood out of your body.

How do the respiratory system and excretory system work together? How does damage in one system affect the other? Consider these questions about respiration and waste removal as you read the following chapter.