Pneumonia

The lung is constantly exposed to airborne infectious agents due to the large surface area of approximately 100 m(2). Therefore pneumonia is one of the most common lung diseases. Understanding infection requires understanding the routes of infections, the way invading organisms infect epithelial cells, as well as defense mechanisms of the lung tissue acquired during evolution. Different variants of infectious and non-infectious pneumonias are discussed; special types of pneumonias such as granulomatous and fibrosing pneumonias are presented under separate sections. Causing organisms and other causes of pneumonias are included, and their mode of action is included as far as understood.