Ukwakhiwa kweqanda: ulwazi jikelele

Iqanda leqanda liyisilonda lesini lesifazane, eliqukethe iqoqo le-haploid lama-chromosomes. Inhloso yalo enkulu ukudluliswa kolwazi lofuzo ngesikhathi sokukhulelwa. Isakhiwo seqanda emvelweni singahluka kakhulu. Isibonelo, iqanda liyi-caviar yezinhlanzi, iqanda lezinkukhu, njll. Inhlobo ngayinye yesilwane inezici zayo.

Isakhiwo se-ovum yezinyoni

Mhlawumbe isibonelo esihle kakhulu salesi sakhiwo yizinyosi zezinyoni nezilwane ezinwabuzelayo, okuyizinhlobo eziningi ezinesakhiwo esifanayo. I-egg liyiqanda elikhulu, okulula ukufunda ngaphandle kwemishini ekhethekile.

Iqanda lenyoni liqukethe i-yolk, amaprotheni negobolondo. Ngayinye yalezi zingxenye ezikhona inezici zayo. I-yolk iyi-dense, ephuzi, ehlangene esakhiwe phakathi kweqanda. Iqukethe amafutha amaningi, amaprotheni, amavithamini, ama-pigments kanye nezici zokulandelela zeqanda. Inhloso yalo enkulu ukuphakela ingane.

Phezu kwe-yolk ihlanganiswe nengqamuzana elincane nelincane lensiza yeltic, lapho ungabona khona indawo encane yokukhanya - i-blastodisk, endaweni eyayiyinhloko yeqanda ngaphambi kokukhulelwa.

Okulandelayo kuza umhlophe weqanda, ohlukaniswe waba amabhola amane. Iqukethe amaprotheni amaningi, amavithamini nezakhi. Ngaphezu kwalokho, kukhona i-lysozyme - i-enzyme ekhethekile ene-antibacterial effect. Ama-gesi kuphela angafaka i-percolate nge-layer ye-protein.

Iprotheyini ihlanganiswe nezinhlamvu ezimbili ezingekho emkhatsini wezinto ezihlala kuzo. I-eggshell iyigobolondo elivikelekile kakhulu lamaqanda, eliqukethe kakhulu i-calcium carbonate. Amagobolondo ama-egg angaba nobukhulu obuhlukahlukene kanye nemibala - lezi yizici zento ngayinye ngayinye.

Ukwakhiwa kwe-ovum yomuntu

Iqanda lesifazane liyisigciwane segciwane eligcinwe futhi livuthwe ezinsizeni ze-ovary. Njengazo zonke izilwane, iseli lomuntu wesilisa lenzelwe ukudlulisela iqoqo lama-chromosomes ngesikhathi sokukhiqiza.

Ngokungafani nama- somatic, amangqamuzana ezocansi akhiwa yi-meiosis, ngakho-ke aqukethe i-haploid kuphela (kubantu abangu-23) isethi yama-chromosomes. Izici zesakhiwo se-ovum yomuntu sizochazwa ngezansi.

Isici sokuqala esihlukanisayo sisayizi. Uma i-cell se-somatic ejwayelekile ingavamile ukufika ku-20 μm, ububanzi beqanda labesifazane bungaba ngu-100 μm. Leli selli lezocansi alinamandla futhi kuze kube sekupheleni kokuvuthwa kwalo ku-follicle.

Ngakho-ke, isakhiwo seqanda sinokufana namanye amangqamuzana omzimba - iqukethe i-nucleus, i-cytoplasm futhi inqunyelwe i- membrane ye-plasma. Njengoba sekushiwo kakade, i-nucleus iyinhlangano ye-haploid. I-cytoplasm iqukethe inani elikhulu le-ribosomes, i-mitochondria, kanye ne-EPS.

Futhi, kulo lonke iseli, lokho okubizwa ngokuthi i-yolk granules kusatshalaliswa ngokulinganayo, okuqinisekisa ukuthi umsoco wesilwane unomzimba kuze kube yilapho ungena odongeni lwe-uterine. Ama-bubbles e-Yolk agcwele izakhi - ikakhulukazi amafutha kanye nenani elincane lama-protein, kanye namavithamini kanye nezici zokulandelela.

Isakhiwo se-ovum sezinsikazi sinezinye izici eziningana. Isibonelo, engxenyeni yangaphandle ye-cytoplasm, kunezinhlamvu ezikhethekile ze-secretory. Phezu kokungena kwe-spermatozoon, okuqukethwe kwe-granules kukhishwa futhi kuthathe isinyathelo kwigobolondo leqanda - ngenxa yalokho, lishintsha isakhiwo salo ukuze kungabi khona i-spermatozoa engangena kuyo.

Kuyathakazelisa ukuthi inani lama-oocyte owesifazane libekwa esikhathini sokuqala sokuthuthukiswa. Kuphakathi nokuthuthukiswa kwama-ovari ukuthi inani elithile le-follicles nama-oocyte seluvele lenziwe ebusweni. Uma siqhathanisa nomzimba wesilisa, inqubo yokwakhiwa kwe-spermatozoa, eqala ngesikhathi sokukhulelwa, iyaqhubeka njalo.

Njengoba ubona, isakhiwo seqanda liqondile futhi lihambisana ngokugcwele nemisebenzi eyenziwa.