Elilodwa - iseli lokuqala eziphilayo ezintsha. Nqanaba yophuhliso elilodwa

Iyunithi ezisisiseko zabo bonke ubomi eMhlabeni iseli. Yeyona ukuyilwa iiseli ezintsha kuvumela umzimba ukuze akhule kwaye aphuhle. Impiliso kunye nesakhiwo zezi yunithi kunzima kakhulu kwaye kuxhomekeke nkcukacha endawo.

Ukuvela igama elithi "elilodwa"

Ukuvela "elilodwa" binzana njengengeniso umphengululi waseJamani Edward Strasburger, ngubani wazahlulela nasekufundweni cytology kunye chromosome theory kwimfuza. Yaba nguye ngenkulungwane XIX kade, bafika kwisigqibo sokuba kuqala hlula iseli wona isityalo, isilwanyana umzimba womntu malunga enye nesigqibo seengcinga efanayo.

Elilodwa: inkcazo

iiseli Sex (gametes) enze ukuzala, oko kukuthi, ngenxa yokuba ubukho babo emzimbeni mhlawumbi ukuzala ngokwesondo. gamete Ibhinqa - kweqanda, amadoda - isidoda. gamete nganye haploid iseti (single) zofuzo.

Le mbono "ontogeny" ibandakanya zonke izigaba zophuhliso ephilayo ukusuka ekuzalweni ukuya ekufeni. ekuqaleni kwawo - kubhaliwe aqhamileyo, oko kukuthi, ezo isidoda neqanda, leyo ebangela ukuba kusekwe a elilodwa. Kuyinto ulwazi yemfuza evela kubazali bobabini. Yintoni elilodwa? Biology unika inkcazelo ngqo kolu luvo. Sinenkangeleko eneenkcukacha kuyo.

Ngaloo ndlela, a elilodwa - Iseli diploid, leyo akhiwa ngxubevange gametes. Diploidy yabangela ngokupheleleyo (ezimbini) iseti zofuzo, elingana zivela gametes zooyise yomama. Uphuhliso elilodwa iqala ngoko nangoko emva kwenkqubo kokukhulelwa, leyo kuthiwa isichumiso.

Cleavage le elilodwa

Emva kokugqitywa kwenkqubo neqanda, iseli ngenxa eshenxela isibeleko. Endleleni, sele ziyaqala ukuhla, kunye nophuhliso yokuwela elilodwa. Le yinkqubo entsonkothileyo eliquka izigaba ezininzi.

Phakathi ngexesha ukuchumisa kwicandelo mitotic lokuqala kunabela malunga 30 iiyure. Eli lixesha xa umzimba lomfazi zonke iinkqubo zokuzilungiselela, ezo ezibalulekileyo kuphuhliso omzimba entsha. Nqanda kumiswa ngakumbi ndiseyimbumba inokuba ezahlukeneyo izinto ezichaphazela imeko umzimba mfazi. Ezo zinto ziquka chromosomal ukuguquka, ngendlela ephosakeleyo yokuphila unina (utywala, iziyobisi, ukutshaya), ukusetyenziswa amayeza athile, izifo kakhulu egazini, njl

Ukusuka elilodwa umbungu. Isigaba sokuqala sale nkqubo - obukhulu. Lo gama ejikelezayo. Emva phakathi kwamacandelo kwinqanaba offline lokukhula yeseli, ngamanye amazwi ngenxa ngamnye kubo ngokuchanekileyo xa iiseli isiqingatha ukuncipha ngobukhulu kuba lincinane. iiseli Ntombi akhiwa ngokukhanywa le elilodwa, zibizwa ngokuba "blastomeres." Inkqubo egaya ihlala kude kube mzuzu xa ayakhekanga ukusuka mbungu. Ngenxa yoko, nathi sithi ukuba umzimba womntu ngenxa-billion emininzi division dollar le elilodwa.

Isigaba blastula kunye gastrulation

Blastomeres luqulathe ngomaleko ezimbini. Bangaphandle emelene iqokobhe ngaphaya. Ibizwa ngokuba trophoblast (zizondlo igqabi), kwaye engaphandle - embryoblast (igqabi osandul). Ngokuthe ngcembe, ngexesha lika kuphindwa phakathi maleko ezimbini kwasekwa umngxuma ngaphakathi apho beqokelela fluid. Eli nqanaba kwisigaba blastula.

Veliswa embryoblast iiseli siphelekwa ukukhula eludongeni lwayo ibinomthwebeba. Ngenxa yoko, kukho imbonakalo embryoblast maleko yesibini eyenza sac igutyana. Kwangaxeshanye nale nkqubo, ubuninzi embryoblast wambumba lwegciwane ezingekazalwa zihlelwe kwenye zezibonda. It is at kweli nqanaba umbungu ifikelela isibeleko. Ngaphezu koko kukho ukukhululwa layo inwebu kunye umzila ngaphaya.

Trophoblast kule nkqubo ludlala indima ebalulekileyo, kuba zaso, enalo iipropati proteolytic, linyibilike epithelium endaweni umbungu afaka ingaphakathi isibeleko. Ngenxa yoko, le epithelium uba mass lactescent.

Isigaba elilodwa yophuhliso ngokukhawuleza kulandelelana. Blastula iguqulelwe ukuba gastrula emele ibhaluni umaleko-mbini. Umaleko engaphandle - na ectoderm, ephantsi - endoderm.

organogenesis

Elilodwa - iseli lokuqala eziphilayo ezintsha. Lonke Isethi kufuneka ubomi kwamaziko ekuqaleni ukusekwa kubo. kanye Inkqubo Abasemagunyeni kwezemfundo ekuthiwa organogenesis. ekuqaleni kwayo kuphawulwa ukuyilwa kwipleyiti uvaleke ukuba kwenzeka ectoderm kwicala amanakani of mbungu. Eminye primordia kuvela namanye amalungu kunye neenkqubo ulusu kunye luvo (ectoderm); sokugaya kwaye isixokelelwano sokuphefumla (ukusuka endoderm); inkqubo musculoskeletal, yokujikeleza, iinkqubo excretory nezenzala (ukusuka mesoderm). Ngaphezu koko, kude kube mzuzu yokuzalwa, ezi zixokelelwano ziyaphuhliswa kwaye ziphuculwe.

uphuhliso post-osandul

Eli xesha luqala ukususela ekuzalweni ukuya lokufikisa. Kuxhomekeka kwinqanaba umbutho eziphilayo, kukho iindidi ezimbini zophuhliso osandul.

1. uphuhliso. Kulo mzekelo, umntwana iimpawu zangaphandle nangaphakathi efana kubazali babo. Umahluko kwi ubukhulu kunye nokungaphuhli kwezinye amalungu. Kuyinto uphawu ukuba iintaka kunye nezilwanyana ezanyisayo, kuquka abantu.
2. uphuhliso engathanga ngqo. Xa olu hlobo lophuhliso, umntwana (Umbungu) iye iiyantlukwano ezininzi kunye nabazali babo. Akumangalisi ukuba amasele nezinambuzane.

Elilodwa - iseli liphinda kweejini abazali. Kodwa inkqubo yophuhliso iiseli ndiseyimbumba aqale bahluka isakhiwo benze imisebenzi ngemisebenzi. Oku kungenxa yokuba iintlobo ezithile genes ukusebenza kwezinye iiseli, ngoxa abanye kwenye indawo. Ngenxa yoko, umzimba yinkqubo noshowo oluxandileyo, isekelwe elilodwa.