posterior pituitary


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Related to posterior pituitary: anterior pituitary

pituitary

 [pĭ-tu´ĭ-tar″e]
1. pertaining to the pituitary gland.
3. a preparation of the pituitary glands of animals, used therapeutically.
pituitary gland an endocrine gland located at the base of the brain in a small recess of the sphenoid bone called the sella turcica. It is attached by the hypophyseal stalk to the hypothalamus and is divided into an anterior lobe (the adenohypophysis) and a posterior lobe (the neurohypophysis), which differ in embryological function and origin. Called also hypophysis.

The adenohypophysis originates from epithelial tissue. The adenohypophysis secretes six important hormones: growth hormone, thyroid-stimulating hormone or thyrotropin, adrenocorticotropic hormone or corticotropin, prolactin, follicle-stimulating hormone, and luteinizing hormone. Most of these hormones are tropic hormones, which regulate the growth, development, and proper functioning of other endocrine glands and are of vital importance to the growth, maturation, and reproduction of the individual. Secretion of the anterior pituitary hormones is controlled by releasing and inhibiting hormones produced by the hypothalamus. Information gathered by the nervous system about the well-being of an individual is collected in the hypothalamus and used to control the secretion of hormones by the pituitary gland. The hypothalamic releasing and inhibiting hormones are transported to the pituitary gland by way of the hypothalamic-hypophyseal portal system in which the hypothalamic venules connect with the capillaries of the anterior pituitary.

The neurohypophysis originates from neural tissue; it stores and secretes two hormones, oxytocin and vasopressin (antidiuretic hormone). These hormones are synthesized in the cell bodies of neurons located in the hypothalamus and transported along the axons to the terminals located in the neurohypophysis and are released in response to neural stimulation.

Surgical removal of part or all of the pituitary gland is called hypophysectomy and is usually done for treatment of a pituitary tumor. Because of its influence on the adrenal cortex and other endocrine glands, removal of the pituitary gland has widespread effects on the body. See hypophysectomy.
The pituitary gland and its relationship to the hypothalamus.
posterior pituitary neurohypophysis.

pos·te·ri·or pi·tu·i·tar·y

the cleaned, dried, and powdered posterior lobe obtained from the pituitary body of domestic animals used for food by humans; an oxytocic, vasoconstrictor, antidiuretic, and stimulant of intestinal motility.
References in periodicals archive ?
Indeed, early papers on pituicytoma (21) suggested a possible origin from folliculostellate cells of the adenohypophysis, but the more recent work (22,23) suggests that all share nuclear TTF-1 immunoreactivity, a feature also shown by the specialized pituitary cells in the normal posterior pituitary gland.
Ectopic posterior pituitary lobe and periventricular heterotopia: Cerebral malformations with the same underlying mechanism?
The second phase of the triphasic response is caused by the uncontrolled release of ADH from degenerating posterior pituitary tissue, or from the remaining magnocellular neurons whose axons have been injured (1).
In this latter condition, the posterior pituitary is appropriately stimulated by the increased plasma osmolality and duly produces sufficient ADH to which the kidney is unable to respond.
Of similar importance, other anterior and posterior pituitary hormone deficiencies should be sought in a child with GH deficiency.
Detailed anterior and posterior pituitary function evaluation of ten patients before treatment is shown in Table 3.
In our patient, we also observed the absence of the high SI in the posterior pituitary lobe.
All patients hospitalized for TBI should undergo an adequate evaluation of anterior and posterior pituitary function.
Additionally, he had no symptoms or laboratory values compatible with posterior pituitary dysfunction.
The expected posterior pituitary bright spot is frequently located in the suprasellar region.
The inferior hypophysial artery enters the ventral region of the posterior pituitary gland.
This inability could result from injury to the hypothalamus, the supraoptic hypophyseal tract, or the posterior pituitary gland (Hickey, 2003).

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