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The pituitary gland or hypophysis is an endocrine gland in vertebrates. In humans , the pituitary gland is located at the base of the brain , protruding off the bottom of the hypothalamus . The human pituitary gland is oval shaped , about 1 cm in diameter, 0.5–1 gram (0.018–0.035 oz) in weight on average, and about the size of a kidney bean .
The anterior pituitary (also called the adenohypophysis or pars anterior) is a major organ of the endocrine system.The anterior pituitary is the glandular, anterior lobe that together with the (posterior pituitary, or the neurohypophysis) makes up the pituitary gland (hypophysis) which, in humans, is located at the base of the brain, protruding off the bottom of the hypothalamus.
The posterior pituitary is not glandular as is the anterior pituitary. Instead, it is largely a collection of axonal projections from the hypothalamus that terminate behind the anterior pituitary, and serve as a site for the secretion of neurohypophysial hormones ( oxytocin and vasopressin ) directly into the blood. [ 2 ]
Schematic of the HPA axis (CRH, corticotropin-releasing hormone; ACTH, adrenocorticotropic hormone) Hypothalamus, pituitary gland, and adrenal cortex The hypothalamic–pituitary–adrenal axis (HPA axis or HTPA axis) is a complex set of direct influences and feedback interactions among three components: the hypothalamus (a part of the brain located below the thalamus), the pituitary gland (a ...
The pituitary gland is divided into three lobes: the anterior pituitary, the intermediate pituitary lobe, and the posterior pituitary. The hypothalamus controls the anterior pituitary's hormone secretion by sending releasing factors, called tropic hormones , down the hypothalamo-hypophysial portal system. [ 3 ]
They may be mistaken for the much more common pituitary adenoma, as well as craniopharyngioma and meningioma. Symptoms from the mass effect of the tumor usually include vision disorders, and less often headaches, hypopituitarism (decreased function of the pituitary gland), fatigue, and decreased libido.
Inferior petrosal sinus sampling (or IPSS), is a diagnostic medical procedure used to determine whether excess adrenocorticotropic hormone (ACTH) is coming from the pituitary gland (usually a pituitary adenoma causing Cushing's disease) or from a source outside the pituitary (a rare tumor causing ectopic ACTH syndrome). The procedure is usually ...
Empty sella syndrome is the condition when the pituitary gland shrinks or becomes flattened, filling the sella turcica with cerebrospinal fluid instead of the normal pituitary. [2] It can be discovered as part of the diagnostic workup of pituitary disorders, or as an incidental finding when imaging the brain.