The lungs are the primary organs of the respiratory system in humans and many other animals including a few fish and some snails.
In humans, the main muscle of respiration that drives breathing is the diaphragm. The lungs also provide airflow that makes vocal sounds including human speech possible.
The lungs are a pair of spongy, air-filled organs found on either side of the chest (thorax). The trachea (windpipe) conducts rancid air to the lungs through its tubular branches, also called bronchi.
The bronchi then divide into smaller and smaller branches (bronchioles), eventually becoming microscopic.
The bronchioles finally end in clusters of microscopic air sacs called alveoli. From the alveoli, oxygen from the air is absorbed into the blood.
Carbon dioxide, a waste product of metabolism, travels out of the blood into the alveoli, in which it can be exhaled.
Involving the alveoli is a thin layer of cells known as the interstitium, which includes blood vessels and cells which help support the alveoli.
The lungs are covered by a thin tissue layer called the pleura. Exactly the same kind of thin tissue lines the inside of the chest cavity â€” also known as pleura.
A thin layer of fluid acts as a lubricant allowing the lungs to slip smoothly as they expand and contract with each breath.
Lung diseases are the most common medical conditions in the world. You found millions of people have lung disease only in the U.S. Infection, Smoking and genes are the main causes of lung diseases.