Light micrograph of three intersecting thyroid follicles. The thyroid gland is composed of follicles, which are structures that contain colloid (pink) and are lined by follicular cells (blue dots). In this image, three adjacent thyroid follicles intersect at the midpoint of the image. A few red blood cells (bright red dots) are also seen in the thin space in between the follicles. Haematoxylin and eosin stained tissue section. Magnification: 400x when printed at 10cm.