Respiration is the process by which humans breathe in air, exchange gases in the lungs, and exhale carbon dioxide back into the air. Oxygen plays an important role in the respiration process.
Entry
When a person inhales, oxygen contained in air enters the body through the nose and the mouth.
Path to the Lungs
Oxygen-rich air travels through the upper and lower respiratory tracts into the lungs.
Alveoli
In the tiniest branches of the lungs, the alveoli remove carbon dioxide and prepare oxygen for transport into the circulatory system.
Diffusion
Oxygen transfers through diffusion from the alveoli to the capillaries. Diffusion is the process of particles of liquids, gases or solids moving from an area of higher concentration to an area of lower concentration.
Capillaries
The capillaries connect to the larger blood vessels, which transport oxygen-rich blood to the heart.
Heart
The heart pumps oxygen-rich blood to the rest of the body through the circulatory system. All of the cells in the human body use oxygen from the blood to break down glucose for energy.
Tags: body through, carbon dioxide, circulatory system, oxygen-rich blood