Imiba yokukhulelwa, ukukhulelwa kunye nokuphuhliswa kwayo ngamaxesha onke aphezulu kwi TOP TOP of the topics of women. Kwaye, ngokukrakra, nangona kunjalo, ulwazi malunga neziseko 'zokuzalwa kobomi obutsha' ngokuqhelekileyo luxhomekeke kwi "biology kunye ne-pestle". Masizame ukubamba kwaye sifunde isakhiwo somnye wabalinganiswa abasemgangathweni yenkqubo - iqanda lomfazi.
Xa kuzalwa intombazana e-ovary, i-endocrine gland ejongene nemvelaphi ye-hormonal, kukho i-getet ze-female ze-7 ze-getet - amaqanda (gametes), ngasinye ngasinye, esichasayo, esinokuthi sibe sisiseko sempilo entsha emva kokuchumisa. Kodwa ngokukhawuleza kunye nobudala, inani lamaqanda liba lincinci: kwiminyaka engama-20 sele sele i-600,000, kwaye emva kwe-60 ayifumaneki nhlobo. Isitokisi esinamandla esinamabhinqa esifazana sivumela umfazi ukuba abe ngumama nokuba ngaba enye okanye inxalenye yesinye i-ovary isuswa.
Ngoko, i-egg cell (iqanda leqanda, i-ovum) lilolona liphilayo likhulu lomzimba womntu, isalathisi sokuzala isalathisi (i-ellyated eliteated or spherical) evelayo kwaye "igcinwa" kwiifollic ovarian. Yenzelwe imimandla kwaye ngaphambi kokufikelela kwisibeleko yenza umendo malunga no-10 cm ubude kunye ne-villi yangaphakathi ye-oviduct ngaphakathi kweentsuku ezingama-4-7. Ubungakanani beqanda buphindwe kabini ngaphezu kobukhulu besilwane se-sperm - iselflegi yesinyama kunye namaxesha ambalwa-ubukhulu bezinye iiseli emzimbeni. Ubungakanani bayo buyingalo ye-100-170 μm. I-gamete yebhinqa ijolise ukuhanjiswa kwenkqubo yokuvelisa i-haploid isethi yama-chromosomes angama-23 (22 i-autosomal idlulisela ngolwazi oluzuzelelekileyo + ngesondo esinye i-X i-chromosome ejongene nesondo lomntwana ongakazalwa).
Ubonakala njani iqanda?
Iskimu sokwakhiwa kweqanda elivuthiweyo, elenziwe emva kwe-ovulation - ukukhutshwa kweqanda kwi-follicle ukuya kwisigxina esiswini, kuboniswe ngezantsi.
Ngokubanzi, iqanda linesakhiwo esifana namanye amaseli omzimba: i-nucleus, i-cytoplasm, umda we-plasma membrane. I-nucleus ye-Haploid eneesethi ze-chromosomes ezingentla apha kwiqanda liphakathi kwayo. I-cytoplasm inezinto ezahlukeneyo ze-ribosomes, izakhi ze-endoplasmic reticulum kunye nezine-enzyme eziyimfuneko ekuphefumulweni kwamaseli e-mitochondrial. Ummandla ongaphandle we-cytoplasm uqulethe i-secretory (cortical) granules, apho ekungeneni kwiqanda le-sperm ikhutshwe, isebenza kwigobolondo yayo, ngenxa yoko iphumela ekutshintsheni kwisakhiwo se-oocyte kwaye ingavumele ukungena kwezinye i-spermatozoa. Izityalo ze-cortical ezisebenzayo ziya kukukhuthaza ukuchumisa ngokuphumelelayo.
Iigobolondo zeqanda nazo zenza umsebenzi okhuselekileyo kunye nomsebenzi wokulungiswa kwesondlo sayo. Ngaphandle, iqanda lijikelezwe ngqabunga elincinci, elihlanganiswe ngqongquthela lwe-microvilli - le yinto ebizwa ngokuba yi-follicular coat okanye isithsaba esikhanyayo.
Umzimba we-polar yiseli encinci, kunye kunye neqanda, eyenziwa njengesiphumo se-meiosis - ukwahlula kweseli ye-progenitor ngexesha lokuvuthwa kwayo. Kuye kwangqiniswa ngokwesayensi ukuba umxholo wequmrhu le-polar lingaba sisiseko sokuxilongwa kwezifo ze-genetic.
Isondlo seseli phambi kokungeniswa kwayo eludongeni lwe-uterine lwenziwa ngoncedo lwe-yolk granules-i-vesicles, ezaliswe ngamafutha, inani elincinane lamaprotheni, iivithamini kunye ne-microelements.
Umgangatho weseli ekhulayo yeqanda, ukusebenza kwayo kungathonyelwa yizinto ezinjalo zempembelelo yangaphandle njengendawo yeselula, ukubunjwa kwezinto eziphilayo kunye nokushisa kwemoya yeqanda. Ukongezelela, indlela yokusebenza kwe-intracellular inefuthe elibalulekileyo kwinkqubo yokukhula kwayo. "Ubuthakathaka", kungekhona iqanda lokuvuthwa kaninzi lubangela ukungabikho komntwana. Oku kunokwenzeka, umzekelo, ukuba umjikelezo wesini uhlala ezinsukwini ezingama-21 okanye ngaphezulu kweentsuku ezingama-35. Ngokweemeko ezinjalo, iseli leqanda "alivuthanga", okanye livele lingafaneleki. Xa kungabikho i-ovulation, ii-ovaries azivelisi iifollic, apho i-ovules ikhulile. Ngaloo ndlela, ngaphandle kwamaqanda, xa i-spermatozoa ingena, ukuchumisa akunjalo.