Anterior pituitary

The adenohypophysis (Latin: adenohypophysis ) - sometimes referred to lax than the anterior pituitary ( HVL ) - represents the greater part of the pituitary gland (hypophysis ) government holds evolutionarily apparent from the Rathke's pouch of mouth bay and is thus often not considered a part of the brain considered, in contrast to the neurohypophysis. During the HVL in humans ( and even -toed ungulates ) represents the anterior part of the pituitary gland that surrounds it with some mammals (eg predators and horses), the neurohypophysis ( posterior pituitary ) completely.

Construction

The structure of the adenohypophysis is typical of an endocrine gland. Here numerous hormones are formed which act as effector or control hormones. The hormone production of the adenohypophysis itself again by releasing hormones ( Liberine ) and Inhibiting Hormone ( statins) of the hypothalamus and usually controlled by the regulated peripheral hormones.

The adenohypophysis consists of three parts:

  • The anterior lobe ( pars distalis ) is the foremost part of the pituitary gland. It contains acidophilic alpha, basophilic beta, gamma and chromophobe acidophilic Etazellen ( = pregnancy cells).
  • The intermediate lobe ( pars intermedia) is located between the anterior lobe and posterior lobe (part of the neurohypophysis ). In its cells melanocyte-stimulating hormone ( MSH) is formed.
  • The funnel lobes ( pars tuberalis ) surrounds the front of the pituitary stalk (part of the neurohypophysis ). About its function is yet unknown.

Glandotrope hormones

Glandotrope ( " glands on acting ," from Latin glandula " gland " ) hormones are tax anterior pituitary lobe hormones that regulate hormone production of other endocrine organs:

  • TSH ( thyroid stimulating hormone) or thyrotropin, stimulates the thyroid gland ( thyroid gland )
  • ACTH ( Adrenokorticotropes hormone), stimulates the adrenal cortex
  • FSH ( follicle stimulating hormone), stimulates the gonads
  • LH (luteinizing hormone), stimulates the gonads

The latter two hormones are summarized as gonadotropins.

Nichtglandotrope hormones

Effektorhormone that have no effect on endocrine glands, but directly on target organs are:

  • STH ( somatotropic hormone) or somatotropin
  • Prolactin
  • MSH ( melanocyte-stimulating hormone ), or which is produced in melanotropin Hypophysenmittellappen

Cell types

Light microscopy can distinguish three cell types by different dyeing behavior in the Adenohyphophyse. It is acidophilic, basophilic and chromophobe cells.

Acidophilic cells

This dyeable with an acidic dye in the cells are most often Adenohyphophse. Characteristic are especially red stainable granules in the cytoplasm. Only form nichtglandotrophe hormones and can be divided into two subgroups:

  • Laktotrophe cells produce prolactin. This cell type has a share of 20 % of the cells of the Adenohyphophyse. In men, they are less common than in women, where they can constitute up to 70 % of the cells in pregnancy. Typical of Laktotrophe cells are relatively large Sekretionsgranula with irregular shape.
  • Somatotrophs cells form the somatotrophs hormone ( STH). Their share in the cells of the Adenohyphophyse is about 50 % and decreases with age. Your granules are smaller.

Basophils

This cell type is due to the trapped in the cytoplasm with basophilic dyes Sekretionsgranula dark violet- blue stainable. Here, too, can be depending on the hormone production of different cell types differ, with all but the MSH - forming cells glandotrophe hormones form:

  • Gonadotrophe cells form the hormones FSH and LH, which act on the gonads. This cell type is relatively large, providing about 10% of all Adenohyphophysenzellen.
  • Thyreotrophe cells make the hormone TSH, which acts on the thyroid gland (Latin thyroid gland ). 5% of all Adenohyphopysenzellen are Thyreotrophe cells, they have small secretory granules.
  • Kortikotrophe cells, which account for about 20% of the cells that produce ACTH, which acts on the adrenal cortex (Latin cortex glandulae suprarenalis ).
  • MSH - producing cells are particularly present in the pars intermedia and represent 5 % of the cells.

Chromophobe cells

Chromophobic cells are not dyeable, as they have no granules. The chromophobe cells include stem cells, stellate cells, which are similar to glial cells in the nervous system, and endocrine consumed, formerly azido- or basophilic cells, which have no more granules.

Rathke's pouch Endocrine system Adrenocorticotropic hormone Follicle-stimulating hormone Human gonad
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