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Pituitary gland
In vertebrate anatomy, the pituitary gland, or hypophysis, is an endocrine gland about the size of a pea and weighing in humans. It is a protrusion off the bottom of the hypothalamus at the base of the brain. The hypophysis rests upon the hypophysial 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). The anterior pituitary (or adenohypophysis) is a lobe of the gland that regulates several physiological processes (including stress, growth, reproduction, and lactation). The intermediate lobe synthesizes and secretes melanocyte-stimulating hormone. 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).
Hormones secreted from the pituitary gland help control: growth, blood pressure, certain functions of the sex organs, thyroid glands and metabolism as well as some aspects of pregnancy, childbirth, nursing, water/salt concentration and the kidneys, temperature regulation and pain relief.
==Structure==
The pituitary gland, in humans, is a pea-sized gland that sits in a protective bony enclosure called the sella turcica. It is composed of three lobes: anterior, intermediate, and posterior. In many animals, these three lobes are distinct. The intermediate lobe is present in many species, in particular in rodents, mice and rats, that have been used extensively to study pituitary development and function, but it regresses in humans at about the 15th week of gestation: it is thus absent from the adult human pituitary gland. In all animals, the fleshy, glandular anterior pituitary is distinct from the neural composition of the posterior pituitary, which is an extension of the ventral diencephalon or Hypothalamus.〔
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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