What is a function of your respiratory system?

Answer 1

Human respiration, as a person takes a breath in the air rushes into the lungs causing the alveoli to expand. The alveoli are like little balloons with air on the inside and tinny blood vessels, called capillaries, surrounding the outside. The lungs expand as the alveoli fill up with air. The concentration of oxygen in the air of the alveoli is higher than the concentration of oxygen in the blood inside the capillaries, which results in oxygen diffusing from the alveoli into the capillaries.

At the same time the carbon dioxide level in the capillaries is high and low in the lungs. So carbon dioxide also diffuses, but in the opposite direction! (carbon dioxide leaves the capillaries and goes into the alveoli)

When a person exhales the lungs decrease in size as the air rushes out.

Quick over view, breathe in:

Oxygen from the alveoli diffuses (enters) into the capillaries

Carbon dioxide from the capillaries diffuses (enters) into the alveoli to be exhaled out.

(note: water vapor is also exhaled out with the carbon dioxide, that is what you see on a cold winter day when you exhale)

or CO2 (carbon dioxide) + H2O (water) vapor out

O2 (oxygen) in