What Is Soil Made Of?
The Science of Breathing (cont.)
When air enters the lungs, oxygen is exchanged between the atmosphere and blood. The cells of our body require oxygen to complete the reactions that allow energy to be released from food. This process, known as aerobic respiration, produces carbon dioxide.
Air enters the body through the nose, where it is warmed and filtered. It travels down the throat and trachea, and into the chest cavity, where the trachea branches into bronchi. Bronchi branch into many alveoli, which are surrounded by very small blood vessels. This allows oxygen to move into the bloodstream and carbon dioxide to move out of the bloodstream.
- Illustration of blood flow in alveoli © helix84, CC-BY-NC 3.0.
- Illustration of bronchi and alveoli © Williams and Wilkins. Licensed for use.
- Moreno N., B. Tharp, and J. Dresden. (2011). The Science of Air Teacher’s Guide. Third edition. Baylor College of Medicine.
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Funded by the following grant(s)
My Health My World: National Dissemination
Grant Number: 5R25ES009259
The Environment as a Context for Opportunities in Schools
Grant Number: 5R25ES010698, R25ES06932