Follicular atresia

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As follicular atresia ( Greek άτρητος without opening ' , latin atresia follicular , English follicular atresia ), the loss or regression of ovarian follicles at any stage, referred So even at primary and secondary follicles. The affected follicles do not ovulate , which is where the term is derived. Follicular atresia occurs at any time in life, but intensifies at certain times ( fetal , postnatal , menarche ). The regression of follicles in the ovary is associated with a reduction in the number of egg cells , in humans from around 1,000,000 at birth to around 400,000 at the beginning of sexual maturity ( menarche ), and is a completely normal process. Of these 400,000 primordial follicles, a maximum of 300 to 450 develop further to the point of fertilization. The atresia of primordial, primary and secondary follicles takes place without any microscopically visible residual structures. In atresia of a tertiary follicle , the basement membrane between the follicular epithelium and theca folliculi, a sheath surrounding the follicle, is greatly thickened and can be detected for a long time as a folded band in the corpus atreticum , a connective tissue scar of the follicle.

Follicular atresia is known in all mammals .

There is an increased tendency to follicular atresia in PCO syndrome due to increased LH levels. The death of the granulosa cells leads to a reduction in aromatase activity , so that fewer androgens can be converted into estrogens , which in turn increases the problem of hyperandrogenemia , i.e. a pathological increase in male hormones, in PCO syndrome.

literature

  • Günther Kern: Gynecology: Brief textbook. Thieme; Stuttgart, New York 1985, ISBN 3-13-460603-8
  • Michael Ludwig, Wolfgang Küpker, Klaus Dietrich: Physiology of the reproductive functions of women. In: Klaus Dietrich (Ed.): Endocrinology and Reproductive Medicine III. (Clinic of Women's Studies and Obstetrics 3) Urban and Schwarzenberg, 4th edition 1998, Munich, 3-36, ISBN 3-541-15034-3
  • RR Greb, K Grieshaber, B Sonntag, L Kiesel: Drug therapy approaches for sterility. GebFra refresher, Thieme 2004, R42 online
  • Christoph Keck, Hermann M Behre: Endocrinology, reproductive medicine, andrology . Georg Thieme, Stuttgart 2002, ISBN 3-13-107162-1 , p. 92 ( limited preview in Google Book search).

Web links

  • Oogenesis in the online embryology course for medical students embryology.ch