What Is Lung Cancer?
Lung cancer is an uncontrolled growth of abnormal cells in one or both of the lungs.
The body is made up of different types of cells that normally divide and multiply in an orderly way. These new cells replace older cells. This process of cell birth and renewal occurs constantly in the body.
Cancer, also known as a malignant growth, occurs when:
- Some cells in the body begin to multiply in an uncontrolled manner
- The body’s natural defenses, such as certain parts of the immune system, cannot stop the uncontrolled cell division.
- These abnormal cells become greater and greater in number, and come together to form a tumor, which is a cellular growth that forms a progressively enlarging mass. A tumor is benign - that is, not a cancer - unless it tends to invade surrounding tissues and organs, in which case it is malignant or cancerous.
Cancerous tumors grow out of control and can invade, replace, and destroy normal cells near the tumor. In some cases, cancer cells spread to other areas of the body.
Lung cancer generally takes many years to develop even though damage to the lungs may occur shortly after a person is exposed to cancer-causing substances.
Nice To Know:
About The Lungs
The air we breathe is taken into the two lungs, situated within the chest. Inside the lungs, oxygen is extracted from the air and carbon dioxide, a waste product from the body, is breathed out. The lungs are cone-shaped and are made up of lobes. The right lung has three lobes and the left lung has two lobes.
Inside the lungs are air tubes, called bronchi. The right and left main bronchi come off the main breathing pipe, and then split up into much smaller tubes within each lung. Those, in turn, branch into thousands of very small airways called bronchioles.
The chest cavity in which the lungs sit is known as the pleural cavity. The smooth lining that surrounds and protects the lungs, enabling them to smoothly expand and contract as we breathe, is called pleura.
Revision date: June 14, 2011
Last revised: by Tatiana Kuznetsova, D.M.D.