Astrid & Hanns-frieder Michler/science Photo Library
Photograph - Photograph
Chronic pneumonia of the lung. Light micrograph of a section of lung tissue diseased with chronic pneumonia. Here, alveolar (air) sacs of the lung are narrowed and engorged with blood (orange). The blood consists of macrophages & neutrophils, white blood cells occurring as an inflammatory response and which fight infection. Lung air capacity is reduced due to this chronic inflammatory exudate. Chronic pneumonia may be diagnosed by a cough that produces a yellow-green sputum. This exudate is usually in response to the presence of pneumo- cocci bacteria, commonly Steptococcus pneumoniae. Magnification: x25 at 35mm size.