Lung cancer, illustration - stock illustration

Annotated illustration of malignant (cancerous) tumours in a human lung. The lungs transport oxygen into the body through breathing. The trachea (windpipe) brings in air through tubular, tree-like branches called bronchi, which then branch into small bronchioles and finally into tiny microscopic sacs called alveoli. The lungs also eliminate carbon dioxide when breathing out. There are many different diseases of the lungs, including cancer.