The intermediate lobe is present in many animal species, in particular in rodents, mice and rats, that have been used extensively to study pituitary development and function. The intermediate is avascular and almost absent in human beings. In many animals, these three lobes are distinct.
It is composed of two lobes: anterior and posterior, with the intermediate lobe that joins the two regions. The pituitary gland, in humans, is oval in shape and is a pea-sized gland that sits in a protective bony enclosure called the sella turcica. Hormones secreted from the pituitary gland help to control growth, blood pressure, energy management, all functions of the sex organs, thyroid glands and metabolism as well as some aspects of pregnancy, childbirth, breastfeeding, water/salt concentration at the kidneys, temperature regulation and pain relief. It regulates hydroelectrolytic stability (by secreting ADH), uterine contraction during labor and human attachment (by secreting oxytocin). The posterior pituitary (or neurohypophysis) is a lobe of the gland that is functionally connected to the hypothalamus by the median eminence via a small tube called the pituitary stalk (also called the infundibular stalk or the infundibulum). The intermediate lobe synthesizes and secretes melanocyte-stimulating hormone. The anterior pituitary (or adenohypophysis) is a lobe of the gland that regulates several physiological processes including stress (by secreting ACTH), growth (by secreting GH), reproduction (by secreting FSH and LH), metabolism rate (by secreting TSH) and lactation (by secreting prolactin). The hypophysis rests upon the hypophyseal fossa of the sphenoid bone in the center of the middle cranial fossa and is surrounded by a small bony cavity ( sella turcica) covered by a dural fold ( diaphragma sellae).
It is a protrusion off the bottom of the hypothalamus at the base of the brain. In vertebrate anatomy, the pituitary gland, or hypophysis, is an endocrine gland, about the size of a chickpea and weighing, on average, 0.5 grams (0.018 oz) in humans.
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