Why and How Do We Breathe?

HOW AND WHY DO WE BREATHE

REFERENCES:

I. Essay pp. 3-5

II. References p. 6

The diaphragm is a muscle in the chest cavity that contracts and relaxes according to signals received by the respiratory center in the brain. In doing so, the diaphragm changes the pressure in the cavity. When the diaphragm contracts, it increases the volume of the chest cavity and lowers the air pressure, thus, air rushes in. This is called inhalation. Exhalation is caused by the relaxation of the diaphragm, which decreases the volume in the chest cavity and increases the air pressure. This causes air to rush out.

Air passes the nostrils and enters the nasal passages where it is warmed, moistened and filtered, by the hairs, mucous, and blood vessels, which line the passages. Hairs collect