RESPIRATORY SYSTEM

The oxygen that we breathe passes into our blood, where it's transported to our muscles.
Our muscles absorb oxygen and expel carbon doxide.
There is an exchange of carbon dioxide for oxygen betwee the blood, and the alveoli.
Then we expel this gas as we breathe out.

1. Mouth and nose: air enters the body through the mouth and nose.
2. Vocal cords: as air passes our vocal cords, they vibrate and enable us to speak.
3. Trachea: this long, rigid tube connects our mouth and nose to our two bronchi. Air travels down the trachea into the bronchi.
4. Bronchi: these two smaller tubes connect the trachea to the lungs.
5. Lungs: these two large bags are connected to the bronchi. The bronchi branch into millions of smaller tubes, or bronchioles, here in the lungs.
6. Bronchioles: these are small tubes inside the lungs. At the end of each bronchiole, there are tiny sacs called alveoli. The air we breathe in goes into these tiny sacs and then passes into blood vessels which surround them.