6The Nose Air enters through 2 openings called nostrils Wall of cartilage separates the 2 nostrilsAir is heated by warm blood flowing through blood vessels in the lining of the nasal cavitiesMucus keeps air moist & keeps tissues from drying out
7The Nose ContinuedMucus along with little hairs called cilia trap tiny particles entering the noseThese cilia also sweep old mucus towards the esophagus & down to the stomach where it is destroyed by hydrochloric acid
13Diaphragm Dome-shaped muscle at the bottom of the lungs. When you breathe in, the diaphragm contracts and flattens out while pulling downward. This movement enlarges the space that the lungs are in. This larger space pulls air into the lungs.When you breathe out, the diaphragm relaxes reducing the amount of space for the lungs and forcing air out.The diaphragm is the main muscle used in breathing.