The term neuroendocrinology refers to the anatomical and functional relationship between the nervous and endocrine system. As originally conceived, it described the fact that nerves located in a distinct area of the brain, the hypothalamus, either secreted their products into a microscopic blood supply to stimulate or inhibit the secretion of the hormones of the anterior pituitary gland or secreted their products into peripheral blood to affect blood volume and pressure, salt concentration and milk ejection from the mammary gland. Such findings led to the idea that the brain was actually another endocrine organ. Later it was appreciated that the secretory products of some of these nerves could actually act on the brain to control sex behavior, drinking and eating behavior, aggressive behavior and maternal behavior.