Kusukela ekuthombeni kuya ekunqamukeni kokuya esikhathini, ama-ovari ayindawo yokusebenza ngezikhathi ezithile. Isigaba sokuqala salo mjikelezo wokuya esikhathini, isigaba se-follicular sihambisana nokuvuthwa kwe-ovarian follicle okuthi, ngesikhathi sokuvuthwa, ikhulule i-oocyte elungele ukuvundiswa. Amahomoni amabili, i-LH ne-FSH, abalulekile kulesi sigaba se-follicular.

Intombazane ngayinye encane izalwa, kuma-ovari, isitokwe sezinkulungwane ezingamakhulu amaningana okuthiwa ama-primordial follicles, ngalinye liqukethe i-oocyte. Njalo ezinsukwini ezingama-28 noma ngaphezulu, kusukela ekuthombeni kuya ekunqamukeni kokuya esikhathini, umjikelezo we-ovarian uyenzeka ngokukhululwa kwe-oocyte - ovulation - ngeyodwa yamaqanda amabili.

Lo mjikelezo wokuya esikhathini wakhiwe yizigaba ezi-3 ezihlukene:

• isigaba se-follicular;
• i-ovulation;
• isigaba se-luteal, noma isigaba se-post-ovulatory.

Isigaba se-follicular siqala ngosuku lokuqala lokuya esikhathini futhi siphela ngesikhathi se-ovulation, ngakho-ke sihlala isilinganiso sezinsuku ezingu-14 (ngaphezu komjikelezo wezinsuku ezingu-28). Ihambisana nesigaba sokuvuthwa kwe-follicular, lapho inombolo ethile yama-follicles okuqala izosebenza futhi iqale ukuvuthwa kwayo. Le folliculogenesis ihlanganisa izigaba ezimbili eziyinhloko:

• ukubuthwa kokuqala kwama-follicle: inani elithile lama-follicles angaphambili (angaba izinkulungwane ezingu-25 zamamilimitha ububanzi) azovuthwa kuze kufike esigabeni se-tertiary follicles (noma i-anthrax);
• ukukhula kwe-antral follicles ku-follicle yangaphambi kwe-ovulatory: enye ye-antral follicles izohlukana neqembu futhi iqhubeke nokuvuthwa, kuyilapho ezinye ziqedwa. Le nto ebizwa ngokuthi i-dominant follicle izofinyelela esigabeni se-pre-ovulatory follicle, noma i-De Graaf follicle okuthi, phakathi ne-ovulation, ikhulule i-oocyte.

Phakathi nesigaba se-follicle, owesifazane akazizwa izimpawu ezithile, ngaphandle kokuqala kokuya esikhathini okubonisa ukuqala komjikelezo omusha we-ovarian futhi ngenxa yalokho ukuqala kwesigaba se-follicular.

“Ama-conductors” alo mjikelezo wama-ovarian amahomoni ahlukene akhishelwa i-hypothalamus ne-pituitary gland, izindlala ezimbili ezitholakala phansi kobuchopho.

• i-hypothalamus ikhiqiza i-neurohormone, i-GnRH (i-gonadotropin ekhulula ihomoni) ebizwa nangokuthi i-LH-RH, ezoshukumisa indlala ye-pituitary;
• ekuphenduleni, i-pituitary gland ikhiqiza i-FSH, noma i-follicular stimulating hormone, ezokwenza kusebenze inombolo ethile yama-primordial follicles abese engena ekukhuleni;
• lawa ma-follicle wona akhipha i-estrogen ezojiya ulwelwesi lwesibeletho ukuze kulungiswe isibeletho ukuze sithole iqanda elingase livundiswe;
• lapho kukhethwa i-follicle yangaphambi kweqanda evelele, ukukhiqizwa kwe-estrogen kukhula kakhulu, okubangela ukwanda kwe-LH (luteinizing hormone). Ngaphansi komphumela we-LH, ukungezwani koketshezi ngaphakathi kwe-follicle kuyanda. I-follicle ekugcineni iyaphuka futhi ikhulule i-oocyte yayo. Kuyi-ovulation.

Ngaphandle kwesigaba se-follicular, akukho ngempela i-ovulation. Lokhu kubizwa ngokuthi i-anovulation (ukungabikho kwe-ovulation) noma i-dysovulation (i-ovulation disorders), kokubili okubangela ukungabikho kokukhiqizwa kwe-oocyte evundiswayo, futhi ngenxa yalokho ukungazali. Izimbangela eziningana zingaba emsuka:

• inkinga nge-pituitary noma i-hypothalamus (i-hypogonadism yemvelaphi "ephezulu"), ebangela ukukhishwa kwehomoni engekho noma okwanele. Ukukhiqizwa ngokweqile kweprolactin (hyperprolactinemia) kuyimbangela evamile yalokhu kungasebenzi. Kungaba ngenxa ye-pituitary adenoma (isimila esiyingozi se-pituitary), ekuphuzeni izidakamizwa ezithile (i-neuroleptics, antidepressants, morphine…) noma izifo ezithile ezivamile (ukwehluleka kwezinso okungapheli, i-hyperthyroidism,…). Ukucindezeleka okuphawulekayo, ukushaqeka ngokomzwelo, ukuncipha okukhulu kwesisindo kungaphazamisa nokusebenza kahle kwale axis ye-hypathalamic-pituitary futhi kuholele ekuphumeni kwesikhashana;
• I-Polycystic ovary syndrome (PCOS), noma i-ovarian dystrophy, iyimbangela evamile yokuphazamiseka kwe-ovulation. Ngenxa yokungasebenzi kahle kwama-hormone, inani elingavamile lama-follicles liyanqwabelana futhi ayikho neyodwa yawo efika ekuvuthweni ngokugcwele.
• ukungasebenzi kahle kwe-ovarian (noma i-hypogonadism yemvelaphi “ephansi”) yokuzalwa (ngenxa yokungajwayelekile kwe-chromosomal, isibonelo i-Turner syndrome) noma etholwe (ngokulandela ukwelashwa ngamakhemikhali noma ukuhlinzwa);
• ukuqala kokuya esikhathini, nokuguga ngaphambi kwesikhathi kwe-oocyte reserve. Izimbangela zofuzo noma zokuzivikela komzimba zingase zibe umsuka walesi simo.

Lapho kukhona i-anovulation noma i-dysovulation, ukwelashwa kokuvuselela i-ovarian kungase kunikezwe isiguli. Lokhu kwelashwa kuqukethe ukukhuthaza ukukhula kwe-follicle eyodwa noma ngaphezulu. Amaphrothokholi ahlukene akhona. Abanye baphendukela ku-clomiphene citrate, i-antiestrogen ethathwe ngomlomo ekhohlisa ubuchopho ekucabangeni ukuthi izinga le-estradiol liphansi kakhulu, okubangela ukuthi ikhiphe i-FSH ukuze ivuse ama-follicles. Abanye basebenzisa i-gonadotropin, amalungiselelo omjovo aqukethe i-FSH kanye / noma i-LH ezosekela ukuvuthwa kwama-follicles. Kuzo zombili izimo, kuwo wonke umthetho olandelwayo, isiguli silandelwa njalo ngokuqapha okubandakanya ukuhlolwa kwegazi ukuze kulinganiswe amazinga e-hormone kanye ne-ultrasound scans ukulawula inombolo nokukhula kwama-follicle. Uma lezi follicle sezilungile, i-ovulation ibangelwa umjovo weHCG.