1.33. Processes of Breathing http://www.ck12.org
1.33 Processes of Breathing
- Outline how the respiratory system and the cardiovascular system work together.
Where does oxygen go in your body?
Once you take in a breath of air, the oxygen doesn’t just stay there in your lungs. It has a lot of traveling to do!
Oxygen has to reach each one of your cells. How do you think the oxygen is moved?
The Journey of a Breath of Air
Breathing is only part of the process of bringing oxygen to where it is needed in the body. After oxygen enters the
lungs, what happens?
- The oxygen enters the blood stream from thealveoli, tiny sacs in the lungs where gas exchange takes place
(Figure1.59). - The oxygen-rich blood returns to the heart.
- Oxygen-rich blood is then pumped through theaorta, the large artery that receives blood directly from the
heart. - From the aorta, oxygen-rich blood travels to the smaller arteries and, finally, to thecapillaries, the smallest
type of blood vessel. - The oxygen molecules move, by diffusion, out of the capillaries and into the body cells.
- While oxygen moves from the capillaries and into body cells, carbon dioxide moves from the cells into the
capillaries. - Carbon dioxide is brought, through the blood, back to the heart and then to the lungs. Then it is released into
the air during exhalation.