人胚胎早期发生II Trilaminar Germ disc (Third Week of Development) 周俊 浙江大学医学院 20180612
Trilaminar Germ Disc (Third Week of Development) 人胚胎早期发生II 周俊 浙江大学医学院 20180612
OBJECTIVES 1. Bilaminar and trilaminar germ discs 2. Describe the formation and derivatives of ectoderm mesoderm and endoderm 3. The components of fetal membrane and their functions 4. Structure and function of placenta 5.comPositionofPlacentabarrier
OBJECTIVES 1.Bilaminar and trilaminar germ discs. 2.Describe the formation and derivatives of ectoderm, mesoderm and endoderm. 3.The components of fetal membrane and their functions. 4.Structure and function of placenta. 5.Composition of Placenta barrier
End of the week of twos Buccopharyngeal Primary 2 major ce‖! masses_membrane Trophoblasts Maternal inner cell mas Amniotic . Trophoblasts cavity Cytotrophoblasts Syncytiotrophoblasts .Embryonic Cavities Extraembryonic somatopleure mesoderm (chorionic plate -Amniotic cavity Extraembryonic coelom Yolk sac ● Germ disc Epiblasts 2GCP89000303000CB00GOLC -hypoblast
End of the Week of Twos •2 major cell masses –Trophoblasts –Inner cell mass •Trophoblasts –Cytotrophoblasts –Syncytiotrophoblasts •Embryonic Cavities –Amniotic cavity –Yolk sac •Germ Disc –Epiblasts –Hypoblasts
Formation of trilaminar disc ● early of three weeks Buccopharyngeal embrane Primitive streak(原条): Cut edge of amnion caudal end a midline Primitive node indentation on the epiblast X-section at"B Primitive streak surface Cloacal membrane Primitive node/knot(原结) Primitive Primitive Primitive pit(原凹) node streak Proliferation Invagination of esbls Amnioblasts epiblasts Intra-embryonic mesoderm Invaginating B erm c Hypoblast
Formation of trilaminar disc •Early of three weeks •Primitive streak（原条）: caudal end, a midline indentation on the epiblast surface •Primitive node/knot（原结） •Primitive pit（原凹） •Proliferation & Invagination of epiblasts Intra-embryonic mesoderm
Gastrulation Cut edge of amnion Migrating epiblasts will form X-section at"B Primitive streak Cloacal membrane Endoderm(内胚层): migrated cells displace hypoblast cells Mesoderm(中胚层): cells btw the endo and ector voblasts Ectoderm(外胚层) (Note-epiblasts=>all layers) Invaginating mesoderm colls Mesoderm cranial and lateral extension fused membranes Oral: oropharyngeal membrane(口咽膜) Cloaca!: cloacal membrane(泄殖腔膜) Cloven membane
Gastrulation •Migrating epiblasts will form: -Endoderm（内胚层）: migrated cells displace hypoblast cells -Mesoderm（中胚层）: cells btw the endo and ecto -Ectoderm（外胚层） (Note - epiblasts=>all layers) •Mesoderm cranial and lateral extension •Fused membranes –Oral: oropharyngeal membrane（口咽膜） –Cloacal: cloacal membrane（泄殖腔膜）