Pituitary gland

Pituitary gland Located at the base of the skull, the pituitary gland is protected by a bony structure called the sella turcica. Median sagittal through the hypophysis of an adult monkey. Semidiagrammatic. Latin hypophysis, glandula pituitaria Gray's subject #275 1275 Precursor neural and oral ectoderm, including Rathke's pouch MeSH A06.407.747 Dorlands/Elsevier h_22/12439692 The pituitary gland, or hypophysis, is an endocrine gland about the size of a pea that sits in the small, bony cavity (sella turcica) at the base of the brain. The pituitary gland secretes hormones regulating a wide variety of bodily activities, including trophic hormones that stimulate other endocrine glands. For a while, this led scientists to call it the master gland, but now we know that it is in fact regulated by hormones released from the hypothalamus. The pituitary gland is physically attached to the brain by the pituitary, or hypophyseal stalk connected with the median eminence. Contents 1 Sections 1.1 Posterior pituitary (neurohypophysis) 1.2 Anterior pituitary (Adenohypophysis) 1.3 Intermediate lobe 2 Functions 3 See also 4 External links Sections It is divided into two sections: the anterior lobe (adenohypophysis) and the posterior lobe (neurohypophysis). Posterior pituitary (neurohypophysis) The posterior lobe is connected to a part of the brain called the hypothalamus via the infundibulum (or stalk), giving rise to the hypothalamohypophyseal tract. Hormones are made in nerve cell bodies positioned in the hypothalamus, and these hormones are then transported down the nerve cell's axons to the posterior pituitary. Hypothalamic neurons fire such hormones, releasing them into the capillaries of the pituitary gland. The hormones secreted by the posterior pituitary are Oxytocin comes from the paraventricular nucleus in the Hypothalamus Antidiuretic hormone (ADH - also known as vasopressin), comes from the supraoptic nucleus in the Hypothalamus Anterior pituitary (Adenohypophysis) The anterior lobe is derived from oral ectoderm, composed of glandular epithelium it communicates with the hypothalamus via a network of capillaries. The anterior pituitary produces and secretes: growth hormone prolactin follicle-stimulating hormone luteinizing hormone thyroid-stimulating hormone adrenocorticotropic hormone endorphins and other hormones It does this in response to releasing hormones produced by the hypothalamus. These travel to the anterior lobe by way of a special capillary system, called the hypothalamic-hypophyseal portal system. These hypothalamic signalling hormones include: TRH (thyrotropin-releasing hormone) CRH (corticotropin-releasing hormone) DA (dopamine, "prolactin inhibiting factor"/PIF) GnRH (gonadotropin-releasing hormone) GHRH (growth hormone releasing hormone) These hormones from the hypothalamus cause release of the respective hormone from the pituitary, i.e. TRH releases TSH, CRH releases ACTH, GnRH releases FSH and LH and GHRH causes the release of GH except for DA, which constantly inhibits the release of prolactin normally. There is also an interaction between the hormones from the hypothalamus, i.e. TRH induces the release of prolactin. The control of release of hormones from the pituitary is in a negative feedback loop. Their release is inhibited by increasing levels of hormones from the target gland on which they act. Intermediate lobe 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, nearly indistinguishable from the anterior lobe. The intermediate lobe produces melanocyte-stimulating hormone (MSH), although this function is often (imprecisely) attributed to the anterior pituitary. Functions The pituitary gland helps control the following body processes: Growth Blood pressure Some aspects of pregnancy and childbirth Breast milk production Sex organ functions in both women and men Thyroid gland function The conversion of food into energy (metabolism) Water and osmolarity regulation in the body See also Growth hormone deficiency Hypopituitarism Acromegaly Pickardt syndrome Pituitary adenoma Sheehan syndrome Syndrome of inappropriate antidiuretic hormone Diabetes insipidus Head and neck anatomy External links The Pituitary Gland, from the UMM Endocrinology Health Guide NeuroNames hier-382 Oklamoma State, Endocrine System Histology at BU 14201loa Endocrine system - Pituitary gland - edit Posterior pituitary: Pars nervosa | Median eminence | Infundibular stalk Anterior pituitary: Pars intermedia | Pars tuberalis | Pars distalis | Somatotropes | Lactotropes | Thyrotropes | Gonadotropes | Corticotropes Endocrine system - edit Adrenal gland | Corpus luteum | Hypothalamus | Kidney | Ovaries | Pancreas | Parathyroid gland | Pineal gland | Pituitary gland | Testes | Thyroid gland Diencephalon - edit third ventricle, interventricular foramina, optic chiasm, subfornical organ epithalamus: pineal body, habenula, habenular nuclei anterior hypothalamus: anterior hypothalamic nucleus, paraventricular nucleus, preoptic area, supraoptic nucleus, suprachiasmatic nucleus intermediate/middle/tuberal/pituitary hypothalamus: infundibulum, median eminence, arcuate nucleus, ventromedial nucleus, dorsomedial hypothalamic nucleus, tuber cinereum, pituitary gland (anterior pituitary, posterior pituitary) posterior/lateral hypothalamus: posterior nucleus, mammillary body, lateral nucleus subthalamus: subthalamic nucleus thalamus: pulvinar, medial geniculate nucleus, lateral geniculate nucleus, list of thalamic nuclei Search Term: "Pituitary_gland" Categories: Glands | Endocrine system | Head and neck | Neuroendocrinology

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