The Job of the Lungs

The lungs are responsible for drawing oxygen into your body and expelling waste carbon dioxide. Once oxygen is in your lungs, it can transfer to your bloodstream and travel throughout the entire body to provide the chemical energy for mitochondria to synthesize energy and power your body's functions. The process of breathing is called respiration, and proper breathing depends on the health, cleanliness and strength of the lungs.

Inhaling

When you inhale, the diaphragm--located directly below the lungs--contracts in order to give the lungs space to expand. Mucous membranes in the mouth and nose trap any solid particles like dust, allowing air to travel on to the trachea, which leads down your throat into two separate channels, one for each lung. These are called the bronchi. The bronchi fork into two more passages. As they diverge, leading farther into your lungs, they become smaller bronchioles. At the ends of the bronchioles are small air sacs called alveoli. There are about 300 million alveoli in an adult human lung, according to maexamhelp.com.

Circulation and Exhaling

The alveoli have blood vessels leading from them to the outside of your lungs and throughout the rest of your body. When your blood passes near the filled alveoli, it picks up a fresh supply of oxygen to give to every cell's mitochondria. The mitochondria produce carbon dioxide as a by-product of their efforts, and this is transferred back into the alveoli to make the reverse journey. Your diaphragm relaxes in preparation to start the whole process over again.

References

• Medical Assistant Exam Help-Alveoli