Vitelline sac mukuzvitakura

Vakadzi vakawanda mushure mekuongorora kwe ultrasound vanofarira mubvunzo uyu: "Chii chinonzi yolk sac pakuzvitakura, uye nei zvichidikanwa?". Ratidza kufarira mune zvose zvine chimwe chinhu chine chokuita ne fetus - izvi zvinowanzoitika. Nokudaro, nhasi tichazotaura pamusoro peiyo iyo yolk sac iri pakuberekwa, uye chii chinoshanda.

Nokudaro, pasi pejinki sac inoreva chimiro chechikamu chemuviri wevanhu. Mune mamwe mazwi, iyo yolk sac mukuzvimba haisi chinhu chinopfuura chikamu chakawedzerwa chemukati mudumbu chiri kunze kwemuviri wevanhu uye inoshandiswa pakupararira kwekutanga uye kutanga kwekugara kwemasero epabonde.

Kuumbwa kwejakak sac panguva yekuzvitakura kunoitwa pamusana pe endoblastic vesicle panguva yekuiswa pasi pazuva rechigumi nemasere rekutswa kweiyoiyo .

Vitelline sac pakuberekwa: kusangana

Mumavhiki ekutanga ekudzivirira (yekutanga-yechipiri trimester), ukuru hwejak sak sac inodarika ukuru hwe embryonic disc uye amniotic cavity. Kutanga nerechitatu trimester, network capillary inoumbwa mu yolk sac, ichipa erythropoiesis foci nyukliya erythrocytes.

Nenzira yakawanda, zvinogona kuonekwa kuti pamubhedha wemunhu, chirongo chepakakamu panguva yekuzvitakura chakakosha, nokuti inhengo yemazuva ano inoita mabasa ezvinonzi "chiropa chepachiropa", kuburikidza iyo iyo inowedzera embryo inogamuchira mapuroteni akadai seal alpha 2-microglobulin, Fetoprotein, nezvimwewo.

Mushure memazuva 28-29 mushure mekugadzirwa kweivo, iyo yolk sac panguva yekubata inowanzova mhedzisiro yakakwana yemasero echipabonde anobva kumativi emadziro kusvika kumabhokisi embryo gonad. Apo chekutanga chetatu inosvika pamagumo, iyo yolk sac inopedza kushanda uye inoshanduka kuva duku shoma yakagadzirwa pedyo nechepasi pemudonzvo wembilical.

Zvakakosha kuti kuderedzwa kwejakak sac panguva yekuzvitakura hakuitike mberi kwenguva, kusvikira nguva apo miviri ye embbryo inogadzirwa pakupedzisira. Kana zvisina kudaro, kuora mwoyo kana kuberekwa kwakanyanyisa hakugoneki.

Chii chinonzi hematopoiesis mu yolk sac?

Pakutanga kwevhiki yechitatu, nzira ye hematopoiesis inotanga, inoratidzirwa nekuparadzaniswa kwezvinyorwa zveropa revascular pamwe nezvinyorwa zvekutanga primary hematopoietic masero ane nucleoli yakakura muyucleus uye basophilic cytoplasm. Nzira ye hematopoiesis yakapedzwa nekuguma kwevhiki yechina yekukura kwemuviri wevanhu, mushure mokunge hemopoiesis inopinda mumatumbu e embryo.

Zvechokwadi, nhasi kune pfungwa mbiri dzekuonekwa kwehematopoietic masero mumumvuri wevanhu. Mazuva ano embryologists uye hematologists kakawanda vanowirirana nedzidziso dzakajairika dzekusagadziriswa kwakabva uye intraembryonic mesenchymal yakabva. Kunyange zvakadaro, nyanzvi dzakawanda uye dzakawanda dzinofanirwawo nemafungiro ekufamba kwemasero kubva pagashi kusvika kumamiti embryonic anoendeswa mberi muzana remakore rapfuura, uchapupu hwaive huongorori hwakaitwa mukurima kwemafu embryo. Mune mavara e embryo, mushure mekurima kwenguva shoma pasina yolk sac, hapana zvachose masero anotangira hematopoiesis. Panguva imwecheteyo, iyo yolk sac, iyo inorimwa isina embryo, inogadzirisa zvakanyanya masero iwayo, izvo zvakare zvakare anosimbisa kuunganidza kwadzo apo kuenderera kune embryo tissue kunoguma.

Zvisinei, inofanira kunzwisiswa kuti mienzaniso yakadaro yekuenzanisa haikwanisi kuva nheyo yezvimwe zvikonzero zvakasimba pamusoro pekuumbwa kwehemopoiesis mumumvuri wemunhu. Kuedza kwakadaro ndiyo mikana mitsva yekunzwisisa zvakajeka kwekugadzirwa kwema embryogenesis kuvanhu mukati mekutanga, uye kwete.