The pituitary gland
, or hypophysis
, is an endocrine gland
about the size of a pea
. It is a protrusion off the bottom of the hypothalamus
at the base of the brain
, and rests in a small, bony cavity (sella turcica
) covered by a dural
fold (diaphragma sellae
). The pituitary fossa, in which the pituitary gland sits, is situated in the sphenoid
bone in the middle cranial fossa
at the base of the brain
The pituitary gland secretes hormones regulating homeostasis, including tropic hormones that stimulate other endocrine glands. It is functionally connected to the hypothalamus by the median eminence.
Located at the base of the brain, the pituitary is functionally linked to the hypothalamus. It is composed of two lobes: the adenohypophysis
. The adenohypophysis
, also referred to as the anterior
pituitary is divided into anatomical regions known as the pars tuberalis, pars intermedia, and pars distalis. The neurohypophysis
, also referred to as the posterior
pituitary. The pituitary is functionally linked to the hypothalamus by the pituitary stalk
, whereby hypothalamic releasing factors are released and in turn stimulate the release of pituitary hormones.
Anterior pituitary (Adenohypophysis)
The anterior pituitary
synthesizes and secretes important endocrine hormones, such as ACTH
, and LH
. These hormones are released from the anterior pituitary under the influence of hypothalamus
. Hypothalamic hormones are secreted to the anterior lobe by way of a special capillary
system, called the hypothalamic-hypophyseal portal system
.it is developed from dorsalwall of pharynx(stomodial part) i.e called as 'ruthke's pouch'. they all transport by special nerve cells present in the hypothalamus.such nerve cells are located in various parts of hypothalamus & send their nerve fibre into median eminence & tubar cinerium(b/w ant. &post. lobe).
Posterior pituitary (Neurohypophysis)
The hormones secreted by the posterior pituitary are
Oxytocin is one of the few hormones to create a positive feedback loop. For example, uterine contractions stimulate the release of oxytocin from the posterior pituitary, which in turn increases uterine contractions. This positive feedback loop continues until the baby is born.
There is also an intermediate lobe
in many animals. For instance in fish it is believed to control physiological colour change. In adult humans it is just a thin layer of cells between the anterior and posterior pituitary. The intermediate lobe produces melanocyte-stimulating hormone
(MSH), although this function is often (imprecisely) attributed to the anterior pituitary.
The pituitary hormones help control some of the following body processes:
Disorders involving the pituitary gland include: