Light micrograph of normal human pituitary gland (hypophysis). The picture shows the junction between the two main lobes of the gland; the anterior lobe (pars anterior, left) and the posterior lobe (pars nervosa, right). The thin layer of columnar cells separating the lobes marks the positon of the pars intermedia. The anterior lobe is the sight of production of many hormones, including trophic hormones which affect the activities of other endocrine glands. It is permeated by a system of blood containing sinusoids seen here as small regions of enucleate cells stained red. Magnification x20 at 35mm size.