Lesson 5-1:
The Respiratory System
Introduction
The Path of Air Inside the Body
The Breathing Process
. . . .

Nostrils and Nasal Cavity

Air goes into your body when you inhale. It passes through the openings of your nose, the nostrils, to the nasal cavity. The blood vessels inside the nasal cavity warm the air. The nose has countless hairs called cilia that filter the dirt. Dirt and dust attach to a sticky substance called mucus.