Pituitary gland

The pituitary gland ( gr ὑπόφυσις hypóphysis " the bottom pendant greenhouse ") is a hormone gland, which plays a crucial overarching role in the regulation of the endocrine system in the body. It is a kind of interface with which the brain through the release of hormones regulate processes such as growth, reproduction and metabolism. The pituitary gland sits in the Turkish saddle ( sella turcica ), a bony cavity of the middle cranial fossa at the level of the nose. A common German name is pituitary gland, the Latin- anatomical term pituitary gland.

Structure and physiology

The pituitary gland is attached to the hypothalamus via the pituitary stalk ( infundibulum ), and is in

• Anterior pituitary ( adenohypophysis or HVL )
• Pituitary, ( HZL )
• Posterior pituitary ( neurohypophysis or HHL )

Divided. Developmentally and functionally the pituitary differ. While the adenohypophysis of a protuberance of the pharyngeal roof, the so-called Rathke's pouch, shows and attaches to the posterior pituitary, the neurohypophysis is an evagination of the diencephalon. This difference is histologically recognizable because while in the adenohypophysis occur several arranged in bales endocrine gland cells dominate in the neurohypophysis especially nerve cell extensions, called axons, whose cell bodies are located in the hypothalamus. Thus, the anterior pituitary hormones is able to form under control of the hypothalamus and the posterior pituitary itself, however, is responsible as a storage and Sekretionsorgan for the hormones produced in the hypothalamus.

Blood supply

The pituitary gland is supplied through four arteries with blood. From the pars cavernosa of the internal carotid artery arise two arteries hypophysiales inferior, forming a capillary network, especially in the area of ​​the posterior pituitary gland, in which the corresponding hormones are released. From the pars cerebralis internal carotid artery arise two arteries hypophysiales the superior that form in the median eminence and the pituitary stalk Primärplexus in which some areas of the hypothalamus their hormones, statins Liberine and secrete. About the venae portales hypophysiales they enter the Sekundärplexus, which lies on the adenohypophysis. In this Sekundärplexus the hormones of the hypothalamus directly to their site of action and it will be delivered the hormones of the adenohypophysis there, from where they are. In the cavernous sinus and thus drain into the systemic circulation to exert their effects

Hormones of the anterior pituitary ( adenohypophysis )

Differences are hormones that act on their target organs ( nichtglandotrope hormones) directly, and those that stimulate the hormone production of downstream endocrine glands ( glandotrope hormones). Directly to their target organs acting growth hormone somatotropin ( STH ) and prolactin. In glandotropen hormones on the gonads ( gonadal ) are acting gonadotrophic hormones follicle stimulating hormone ( FSH) and luteinizing hormone (LH ) and the nichtgonadotropen hormones, namely, the adrenal cortical stimulating adrenocorticotropic hormone (ACTH) and thyroid stimulating thyroid stimulating hormone (TSH ) distinguished. By processing of a larger precursor peptide of Proopiomelanocortins developed in addition to ACTH also melanotropin (MSH ), β - endorphin and met- enkephalin. The hormone production of the pituitary gland is controlled by Liberinen and statins by the hypothalamus.

Hormones of the pituitary intermediate lobe

The pituitary, among other things, education center of the melanocyte stimulating hormones (MSH, melanotropins ).

Hormones of the posterior pituitary ( neurohypophysis )

Among the hormones which are stored and distributed in hypophysis, are oxytocin and antidiuretic hormone (ADH), which is also known as antidiuretic or vasopressin. ADH in the supraoptic nucleus ( core area, which is located above the optic nerve ), oxytocin in the paraventricular nucleus formed ( core area in the hypothalamus ) of hypothalamus.

Diseases and diagnostics

An underactive pituitary gland ( hypopituitarism, panhypopituitarism ) can have many causes.

Tumors of the anterior pituitary gland is called pituitary adenomas. They often cause excessive hormone production. Overproduction of ACTH results in a central Cushing's syndrome, growth hormone excess, typically in an increase in the size of hands and feet ( acromegaly). Large tumors can press on the optic nerves, which leads to significant vision problems. If left untreated, blindness is the result. Such tumors are surgically removed frequently through the nose, usually can see right after surgery, the patient returned to normal.

At the physical examination is followed by hormone measurements and functional tests. If there is clinical suspicion hormone tests should be carried out at an endocrinologist before imaging, as the imaging method often result in false-positive findings ( " Incidentalome "). As imaging techniques find the radiograph of the sella turcica in Seitbild of the skull, computed tomography, magnetic resonance imaging and somatostatin receptor scintigraphy application.