Ukuthuthukiswa kanye nesakhiwo gametes

Isakhiwo wesilisa, gametes zesifazane kuholela ukugcwaliseka umsebenzi wawo obaluleke kakhulu. - ekusebenziseni ukukhiqizwa kabusha okuzala. Kuyinto eziyizici abameleli kokubili ezitshalweni nasezilwaneni. izici Bezakhiwe kwamaseli lwegciwane kuzoxoxwa ngakho esihlokweni sethu.

Gametes: ubuhlobo lokuphatselene nesakhiwo nemsebenti

namangqamuzana akhethekile othola inqubo yokuzala okuzala abizwa ngokuthi gametes. Iduna nensikazi ubulili amaseli - sperm amaqanda - kukhona haploid, okusho isethi eyodwa wama-chromosomes ... isakhiwo esinjalo inikeza gametes genotype i umzimba, ezakhiwe ekubumbaneni zabo okuyinto. Uyena diploid, noma kabili. Ngakho, ingxenye ulwazi zofuzo i umzimba uthola kusukela kunina, kanti enye ingxenye yaba - kuyise.

Naphezu ukufana, isakhiwo wobulili amaseli zezitshalo nezilwane ngezindlela eziningi ezahlukene komunye nomunye. Lokhu kusebenza ikakhulukazi ezindaweni ezithile kumiswa yabo. Ngakho, ngo-isidoda angiosperms ise anthers ka stamens, kuyilapho Iqanda - e esibelethweni we pistil. izilwane ezinamangqamuzana amaningi banemizimba ekhethekile - le wendlala yabesilisa, okuyinto kumiswa gametes: ova - e ezikhiqiza amaqanda kanye nesidoda cells - ku testes.

Inqubo gametes ukwakha

Ukwakheka kanye nokuthuthukiswa germ cells kunqunywa inkambo gametogenesis - inqubo kumiswa zabo, ebanjwa in izigaba eziningana. Phakathi isigaba zizalela we gametes eyinhloko zihlukaniswe kaningana mitosis. Nakuba nokugcina iqoqo double lezakhi zofuzo. Ngo abantu abesilisa nabesifazane ezahlukene, lokhu sigaba has umehluko yayo. Ngakho, ngo-ezincelisayo wesilisa, uqala lapho kuqala zokuthomba futhi ihlala kuze nokuguga. Esikhathini division lensikazi primordial germ cells kwenzeka ngesikhathi kuphela kwengane esiswini umbungu. Kuze ukuthomba, azigcina ithule.

Isigaba ukukhula okulandelayo. Kule nkathi gametes eyinhloko sikhule ngobukhulu, ukufanisana kwenzeka DNA (ukubuyelela kabili). Inqubo ebalulekile futhi isitoreji izakhi, ngoba kwadingeka kwezinhlelo ukwahlukana okwalandela ngeke.

Esigabeni yokugcina gametogenesis ibizwa ngokuthi esigabeni sokukhula. Ngokuhamba yayo eyinhloko ubulili amaseli wehlukanisa meiosis - meiotic. yi salo ezine amaseli haploid ethathwe diploid eyinhloko.

spermatogenesis

Ngenxa yalokho, ukwakheka gametes wesilisa, t. E. Spermatogenesis kwakhiwa ezine isakhiwo ezifanayo futhi egcwele. Sinenkosi ikhono zalisa. Isakhiwo amaseli besilisa zokuzala, ngokunembile, isici salo ukubukeka ezincwadini ezithile. Ikakhulukazi, lo msila, okuyinto ukulawula ukuhamba gametes besilisa. Le nqubo ithatha indawo esigabeni odlule kumiswa ezengeziwe, okuyinto sici kuphela inqubo spermatogenesis.

ovogenesis

Ukwakheka zesifazane germ cells, kanye inqubo kumiswa yabo (oogenesis) enezinto eziningi izici isici. Nge ekukhuleni kwamangqamuzana oocytes ngesikhathi meiotic esizayo cytoplasm Ukuboshelwa wadibaniswa amaseli. Kuphela omunye wabo ngenxa yokuthola iqanda uyakwazi zisenza sibe nokuphila kwesikhathi esizayo. Abanye abathathu eziguqulelwa ithole isiqondiso futhi umphumela libhujiswa. Okwakushiwo walesi nqubo ukunciphisa inani kwamaKristu avuthiwe, akwazi zalisa insikazi gametes. Kuphela ngaphansi kwalesi simo, kuphela iqanda ungathola lemali edingekayo kwezakhi kubalulekile ekuthuthukiseni ikusasa umzimba. Ngenxa yalokho, ngesikhathi owesifazane uyakwazi ukuba nabantwana, ikhono ukwakha ingqikithi 400 ubulili amaseli. Ngenkathi amadoda bangamaphesenti abangamakhulu ezigidi.

Isakhiwo germ cells besilisa

Isidoda amaseli amaseli elincane kakhulu. usayizi wabo ngokulambisa a micrometer ambalwa. Ubunjalo Ubukhulu ezinjalo, yebo, ihlawulelwa ngokwesibalo sako. Isakhiwo ubulili amaseli leduna umzimba has izici zayo siqu.

Spermatozoon ziyahlangana siqukethe ekhanda, emqaleni nasemhlane umsila. Ngayinye yalezi izingxenye wenza imisebenzi ethile. Inhloko has a organelle unomphela yeselula ye eukaryotes - ikhenela. Kuyinto esiphathiswa ukwaziswa kwezakhi zofuzo eziqukethwe molecule e-DNA. Linikeza umnyombo ukuwudlulisa isitoreji impahla sitholwa njengefa. Uphiko ikhanda isidoda lesibili acrosome. Lesi sakhiwo beshintsha Golgi eziyinkimbinkimbi futhi inike enzyme ethize uyakwazi Ukuqedwa igobolondo amaqanda. Ngaphandle kwayo, inqubo sokukhulelwa akunakwenzeka. I organelles entanyeni kukhona mitochondria, okunikeza ukuhamba umsila. Kule ngxenye isidoda futhi centrioles. Lezi organelles zidlala ababalulekile lokuphotha ukwakheka ngesikhathi cleavage iqanda eselivundisiwe. kwakhiwa microtubules ukuthi usebenzisa amandla mitochondria ukunikeza ukunyakaza gametes besilisa Umsila kwesidoda is.

Isakhiwo iqanda

Female lwegciwane amaseli inkulu kakhulu kunangendlela isidoda. ubukhulu yabo ezincelisayo isesikhathini 0.2 mm. Kodwa isibalo esifanayo e Crossopterygii 10 cm, kuyilapho porbeagle -. Ukuze 23 cm ngokungafani kuya wesilisa ocansini Iqanda amaseli awashintsheki. Banezinhliziyo round ukuma. Esikhathini cytoplasm kula maseli iqukethe semali reserves egcinwe kwezakhi ngesimo Iqanda isikhuphasha. Ngaphezu kwalokho i-DNA core abathwele ukwaziswa kwezakhi zofuzo, kunesinye nucleic acid - RNA. Liqukethe ulwazi mayelana nokwakheka amaprotheni ezinkulu umzimba esizayo. Isikhuphasha neqanda angase abekwe engalingani. Ngokwesibonelo, Amphioxus nguye maphakathi, nezinhlanzi kuthatha cishe bonke ubuso, ukusunduza nucleus futhi cytoplasm komunye izinti iseli. Ngaphandle amagobolondo amaqanda ivikelwe: isikhuphasha, kanye esobala yangaphandle. Lokho banayo ukuncibilikisa acrosome ikhanda isidoda ukuba sifeze inqubo sokukhulelwa.

kokukhulelwa izinhlobo

Lokuphatselene nesakhiwo nemsebenti lwegciwane amaseli banesibopho ukuqaliswa inqubo sokukhulelwa - nokuhlanganiswa gametes. Kule nqubo, izinhlayiya eziyisisekelo zofuzo of gametes kuhambisane core olulodwa, futhi kwakhiwa zygote is. Nanguya iseli wokuqala umzimba omusha.

Kuye esikhundleni ukudlula inqubo ababonakali ngezikhundla yangaphandle (ngaphandle) kanye yangaphakathi kokukhulelwa. Uhlobo lokuqala wenziwa yomzimba amagundane zesifazane. Lokhu kujwayele ukwenzeka imvelo yasemanzini. Izibonelo zezinto eziphilayo okuyiwona kukhona kokukhulelwa zangaphandle, kukhona amalungu esigaba zezinhlanzi. abesifazane babo amaqanda emanzini lapho owesilisa yayo waphuzisa uketshezi kwesidoda. Isibalo amaqanda yezilwane ezisebenzayo njengalezi kuze kufinyelele ayizinkulungwane eziningana, lapho ikhona futhi ikhula hhayi abantu kangaka. Iningi lawo sidliwe izilwane zasemanzini. Kodwa zonke izilwane ezincelisayo libhekene kokukhulelwa yangaphakathi, okuyinto eyenzeka ngaphakathi emzimbeni owesifazane ngosizo ezikhethekile besilisa copulative izitho. Isibalo amaqanda isilungele kokukhulelwa, incane.

Isakhiwo amaseli iduna nensikazi zokuzala kwesimiso sokuzala izitshalo sihluke kakhulu elesilwane. Ngakho-ke gametes uhlangane inqubo lihlukile. ubulili amaseli Male izitshalo ungenalo umsila futhi abakwazi ukuthutha. Ngakho-ke, kokukhulelwa ekulandulayo impova. Le nqubo sokudlulisela impova kusuka anther yenhlamba stamens. Sekwenzekile umoya, izinambuzane noma abantu. Caught ngendlela ku inhlamba, kwehlisa isidoda lwegciwane tube e yayo ingxenye enwetshiwe ephansi - esibelethweni. Kukhona iqanda. Ngezinye confluence gametes kwakhiwa imbewu umbungu.

Umqondo parthenogenesis

Isakhiwo amaseli lwegciwane, e abesifazane ikakhulukazi, kusenza sikwazi yezindlela esiyinqaba ukuveza okuzala. Ibizwa ngokuthi parthenogenesis. essence yayo begazi itholakala ukuthuthukiswa omdala kweqanda unfertilized. Le nqubo ibizwa ebonwe ngibone umjikelezo wokuphila kwe ezinamagobolondo Daphnia lapho enye isizukulwane ngokobulili futhi parthenogenetic. Female iseli zokuzala iqukethe umsoco ngokwanele ukuba kuphakame impilo entsha. Nokho, uma kungekho parthenogenesis inhlanganisela entsha ukwaziswa kwezakhi zofuzo, futhi ngenxa yalokho, ukubukeka izinhlamvu ezintsha ngangokunokwenzeka. Nokho parthenogenesis kuyinto okubalulekile yemvelo ngoba kwenza inqubo ukuzala kungenzeka ngisho engekho ngabanye abantu bobulili obuhlukile.

Isigaba of umjikelezo wokuya esikhathini uwubufakazi

Esikhathini insikazi germ cells akuzona njalo isilungele kokukhulelwa, kodwa othile izigaba nomjikelezo wokuya esikhathini. Kule nqubo bokuphila emzimbeni kwenzeke izinguquko cyclically njalo nemisebenzi uhlelo zokuzala. Le nqubo kulawulwa uhlelo humoral. Isikhathi salesi umjikelezo izinsuku ezingu 21-36 nge-avareji ka-28 Isikhathi kungenziwa ihlukaniswe izigaba ezintathu. Esikhathini sokuqala (kokuya esikhathini) ezisabalele cishe zokuqala ezingu-5, endometrium sinqatshelwe. Lokhu kulandelwa ukudabuka emincane yegazi. 6-14 ngosuku ngaphansi kwethonya pituitary follicle imele lapho iqanda ukuvuthwa. Lining kwesibeletho ngalesi sikhathi liqala ukuba alulame. Lona isigaba essence poslemenstrualnoy. Kusukela 15 th-28 ngosuku th kwetinhlavu izicubu okunamafutha zezinzwa - the luteum Corpus. It ukhonza njengelungu endocrine indlala yesikhashana ukuthi bukhipha ama-hormone ukuthi zivimbela nokuvuthwa of follicle. Esikhathini kusuka 17 th-21 ngosuku th of amathuba fertilization aphakeme. Uma lokhu kungenzeki, ubulili cell libhujiswa ulwelwesi lwamafinyila is ehlutshiwe emuva.

Uyini-ovulation

Ngosuku lwe-14 umjikelezo wokuya esikhathini uwubufakazi isakhiwo amaseli zesifazane zokuzala sishintsha kancane. Igobolondo amaqanda iphula follicular futhi ukhululeka esibelethweni ukuze tube fallopian. Kwaba kukhona ukuthi uqeda nokuvuthwa kwawo. Le nqubo ibizwa ngokuthi yi-ovulation. Lena inkathi ebaluleke kakhulu, futhi phakathi naleso kwesibeletho ozuza nekhono lokwamukela iqanda eselivundisiwe.

Chromosome iqoqo gametes

Amaqanda kanye nesidoda ube isethi eyodwa ukwaziswa kwezakhi zofuzo. Ngokwesibonelo, ubulili amangqamuzana omuntu aqukethe 23 Ama-chromosomes e, kanye zygote - 46. Ngesikhathi confluence gametes isigamu izakhi zofuzo i umzimba uthola kusuka unina, futhi ingxenye yesibili - kuyise. Lokhu kusebenza futhi phansi. Phakathi ovelele Ama-chromosomes e autosomes nokukodwa pair of ocansini. Basuke ebekwe zesi-Latin. Kubantu, amaseli zesifazane aqukethe-chromosomes ezimbili ezifanayo ubulili, kuyilapho amadoda - ezahlukene. Amagciwane Engeke Esaba amaseli aqukethe omunye wabo. Ngakho, ubulili komntwana kuncike ngokuphelele emzimbeni besilisa uhlobo wama-chromosomes oqhubeka isidoda.

Umsebenzi lwegciwane amaseli

Isakhiwo amaseli enzalo besifazane, kanye amadoda, kuhlobene ne imisebenzi abasenzela. Njengengxenye uhlelo zokuzala, abasenzela okuzala ukukhiqizwa kabusha umsebenzi. Ngokungafani asexual, okuyinto elondoloza ubuqotho ulwazi zofuzo i umzimba, ukuzala ivumela kudalwa izici ezintsha. Lesi isimo ezidingekile okuvela lithathelwe, futhi ngenxa yalokho lonke khona izinto eziphilayo.