Getting the Air in There
When you inhale air through your nostrils, the air enters the nasal passages and travels into your nasal cavity. The air then passes down the back of your throat into the trachea (say: TRAY-kee-uh), or windpipe, on its way to the lungs.
Your nose is also a two-way street. When you exhale the old air from your lungs, the nose is the main way for the air to leave your body. But your nose is more than a passageway for air. The nose also warms, moistens, and filters the air before it goes to the lungs.
The inside of your nose is lined with a moist, thin layer of tissue called a mucous membrane (say: MYOO-kus MEM-brayne). This membrane warms up the air and moistens it. The mucous membrane makes mucus, that sticky stuff in your nose you might call snot. Mucus captures dust, germs, and other small particles that could irritate your lungs. If you look inside your nose, you will also see hairs that can trap large particles, like dirt or pollen.
If something does get trapped in there, you can probably guess what happens next. You sneeze. Sneezes can send those unwelcome particles speeding out of your nose at 100 mph!
Further back in your nose are even smaller hairs called cilia (say: SILL-ee-uh) that you can see only with a microscope. The cilia move back and forth to move the mucus out of the sinuses and back of the nose. Cilia can also be found lining the air passages, where they help move mucus out of the lungs.