September Gallery

Brain Scan

Obsessive-compulsive disorder. Coloured Positron Emission Tomography (PET) scans of a human brain, showing active areas in obsessive compulsive disorder. The brain is sectioned axially (left), sagittally (centre), coronally (at right). In this patient, positive correlations (activity increases as symptoms get stronger) are in the top row, seen coloured in the left orbital region, prefrontal, left frontal gyri and thalamus. Negative correlation (activity decreasing as symptoms strengthen) are in the bottom row in the right frontal gyrus and parietal regions. Active areas coloured red/yellow show blood flow detected by a radioactive tracer

© Wellcome Dept.Of Cognitive Neurology/Science Photo Library

Illustration of lung bronchioles and alveoli

Illustration of lung bronchioles and alveoli. The lung consists of many branched air passages called bronchioles (upper left), which end in groups of tiny balloon-like sacs called alveoli. It is in each alveolus that gases are exchanged during re- spiration. The bronchiole walls are lined spirally with smooth muscle (here, coloured orange). The alveolar sacs are thin-walled and supplied with a capillary network of blood vessels. Pulmonary veins (blue) bring deoxygenated blood to the lungs which is oxygenated by gas exchange across the alveolar walls (see lower left). Arteries (red) transport this oxygenated blood to the body. There are about 300 million alveoli in a human lung

© John Bavosi/Science Photo Library