The journey of oxygen through your lungs

Pathway of Air Flow
Our journey of oxygen into the lungs and back begins when the brain stem sends a message to the diaphragm which is a muscle under the lungs.
As the diaphragm moves down the lungs expand.

Air enters the nose and mouth and enters the nasal passages.
Your nose and nasal passages have tiny hairs called cilia and mucus that help filter dirt and pollen out of the air.
The air next moves to the pharynx which is located at (the back of the mouth)
From the pharynx, it moves to the larynx which is commonly called the voice box.
the voice box (makes sounds when air
passes over the vocal cords)
Epiglottis: the flap of connective tissue that covers
over the larynx during breathing
It stands open during breathing, allowing air into the larynx. During swallowing, it closes to prevent choking on food

From the larynx, air travels to the Trachea which is a rigid tube made of cartilage.
The trachea leads into two tubes called the left and right bronchus
These tubes continue to branch until you reach a tiny air sac called a alveoli
At the alveoli, oxygen diffuses into the capillaries and carbon dioxide diffuse into the alveoli and is exhaled.
This process is repeated over and over again.
Updated Version
   • Respiratory System Basics