JOHN BAVOSI / SCIENCE PHOTO LIBRARY JOHN BAVOSI / SCIENCE PHOTO LIBRARY
Thyroid gland. Illustration of the human thyroid gland, with coloured spheres representing the hormones it produces and those that control it. The thyroid gland, wrapped around the windpipe (bottom) at the front of the neck, consists of two soft lobes (red) joined by a small isthmus. It makes two hormones, triiodothyronine & thyroxine, shown here as yellow spheres, which control the way the body uses chemical energy. The level of these hormones in the blood is delicately controlled by thyroid-stimulating hormone (blue spheres), which is made by the pea-sized pituitary gland (top) in the base of the brain. Upset in the balance of these hormones causes serious illness.
Model release not required. Property release not required.