Images Dated 4th March 2004

Pulmonary disease

Chronic obstructive pulmonary disease. Artwork of a bronchus and alveoli of the lungs in chronic obstructive pulmonary (or lung) disease (COPD). COPD is a combination of emphysema and chronic bronchitis. Lung bronchi (upper right) divide to form alveoli (air sacs). These are the terminal portions of the lung's air passages, where oxygen and carbon dioxide transfer between the air and the blood (capillaries are red and purple). The cutaway sections reveal that the alveoli are filled with sputum (phlegm, yellow). COPD causes shortness of breath and can lead to oedema and heart failure. It is usually caused by smoking and damage is irreparable

© John Bavosi/Science Photo Library

Atherosclerosis

Atherosclerosis. Artwork of a human heart showing narrowing of the coronary arteries due to atherosclerosis, a build up of fatty deposits (atheroma, yellow) on the artery wall. The large red vessel is the aorta, the main artery carrying blood from the heart to the body. Two coronary arteries arise from the aorta and supply the heart muscle with oxygen. The left coronary artery (on the right) divides into the anterior descending and circumflex branches. Coronary artery disease is the most common cause of death in developed countries. The narrowing causes abnormal clotting, which blocks the vessel and starves the heart's muscle of blood, causing a heart attack

© JOHN BAVOSI/SCIENCE PHOTO LIBRARY

Volcano caldera formation

Caldera formation. Artwork of the formation of a caldera, a large basin-shaped volcanic depression. Calderas may form when a volcano (top) undergoes a massive eruption (upper centre). This creates a much larger crater than the original volcanic vent (lower centre). Alternatively, the volcano may collapse inwards. Over time the magma chamber beneath the caldera solidifies and the volcano becomes dormant or extinct. The caldera may then fill with water to form a lake (bottom). Renewed volcanic activity may lead to the formation of new volcanic cones within the caldera. A well- known caldera lake is Crater Lake in Oregon, USA, which is more than 600 metres deep

© GARY HINCKS/SCIENCE PHOTO LIBRARY