Day22-cell stageDay34-cellstageDay4MorulaActualembryoDay5Day1BlastocystFirstcleavageFeedingcellsDayOCorpusFertilizationluteumDay6BlastocystattachesOvaryampullaDay7SpermEmplantingembryohCGOvum(12-24h)OviductEstrogenandDay10OvulationprogesteroneImplantedembryoMaintains uterine liningChorionfrom10daysuntilendofsecondmonthUterinelining(a)
ampulla (12-24h)
4.Bilaminar Germ DiscAmnioticcavitysyncytiotrophoblastEpiblastExtra-embryonicPrimitivemesodermyolk sacHypoblastEmbryonicDisk
Extraembryonic mesoderm Embryonic Disk 4. Bilaminar Germ Disc Hypoblast Amniotic cavity Epiblast Primitive yolk sac syncytiotrophoblast
FormationofAmnioniccavityandYolkSacAmnioniccavitySplanchnicoSomaticCREEORDcb000800Embryonic990000disk.aExtraembryonicExtraembryoniccavitymesodermoo006c..odooao.0eB00DPrimaryvillus5.cccoaocc.oo.ooo...ooo.amYolk sacFunction: protection and nutrition
Formation of Amnionic cavity and Yolk Sac Function: protection and nutrition Amnionic cavity Yolk sac Extraembryonic mesoderm Embryonic disk Extraembryonic cavity Primary villus Splanchnic Somatic
Formationof extraembryoniccavity&BodyStalkVilliBody StalkeASplanchnicExtraembryonicmesodermSomaticExtraembryoniccavityBody stalk: the connection structure between thedisk/amnionic cavityandtrophoblastsUmbilicalCord
Formation of extraembryonic cavity & Body Stalk Body stalk：the connection structure between the disk/amnionic cavity and trophoblasts. Body Stalk Extraembryonic mesoderm Splanchnic Extraembryonic cavity Somatic Villi Umbilical Cord
合体滋养层细胞滋养层波养层陷窝血管AreaofprochordalplateCut edgeofamnionepiblasthypoblastWallofyolksac初级卵Primitive0黄素streakEpiblastHypoblast胚体体腔膜凝栓Period oftwos:EpiblastEmbryoincDisk2flat germ layersHypoblast2trophoblastlayers?When:by the 2nd week2cavities
Epiblast Hypoblast Embryoinc Disk ? When： by the 2nd week Period of twos: 2 flat germ layers 2 trophoblast layers 2 cavities epiblast hypoblast
SummarySperm FertilizationCleavageZygoteMorulaOvumAmnioniccavityEndometrium(2 W)Ecto+-EpiblastEmbryonicICMBlastocystDiskimplantationEndo---hypoblastCavityYolksacCyto-BasalisTrophoblastCapsularisDecidualSynParietalisSomatopleureExtra-SplanchnopleureEmbryonicmesodermBodystalk
Sperm Ovum Zygote Morula Blastocyst Endometrium Fertilization Cleavage Trophoblast Cavity ICM Decidual Basalis Capsularis Parietalis Embryonic Disk （2 W） CytoSynExtraEmbryonic mesoderm Splanchnopleure Somatopleure Body stalk Amnionic cavity Yolk sac Endo-hypoblast Ecto- Epiblast implantation Summary
5.Trilaminar Germ layers (week3)Formation of primitive streak4561.Primitivestreak023Rostral2.PrimitivenodeaU9epiblastic cells-primitive streak(primitivegroove,primitivenode)
5. Trilaminar Germ layers (Week 3 ) Formation of primitive streak epiblastic cells →primitive streak (primitive groove, primitive node ) 1. Primitive streak 2. Primitive node
Cut edgeofamnionYolk sacPrimitiveEpiblaststreakAmnionCutB-YolkAInvaginatingHypoblastsacPrimitivemesodermcellsPrimitivenodestreakSignificance: 1) determine the middle axis ;2) determine cranial-caudal-axis;3) Induce mesoderm
Significance: 1) determine the middle axis ; 2) determine cranial-caudal-axis; 3) Induce mesoderm Cut
PrimitivenodePrimitivestreakAmniotic cavityEpiblastYolkSacDevelopingHypoblastmesodermalcells? When: By the end of the 3rd Week?What:Formation of the trilaminargermlayers(allfromepiblast)
? When: By the end of the 3rd Week, ?What: Formation of the trilaminar germ layers Epiblast Primitive node Primitive streak Yolk Sac Developing Hypoblast mesodermal cells Amniotic cavity (all from epiblast)
FormationofNotochordCranialcauPrimitivenodeCaudalEpiblastcells-→primitivenode-→notochordal (head)process
Epiblast cells → primitive node → notochordal (head) process Formation of Notochord Primitive node Cranial Caudal