2. Good Afternoon Everyone

3. Fetal membrane and placenta 1. Fetal membrane chorion yolk sac amnion allantois umbilical cord Ⅴ.Ⅴ.

4. Chorion Formation Secondary stem villi chorion villi chorionic plate Structure of villi Primary stem villi

5. syncytiotrophoblast cytotrophoblast extraembryonic mesoderm with blood vesselsblood vessels Secondary stem villi: syncytiotrophoblast cytotrophoblast extraembryonic mesoderm 固有胎盘绒毛 definitive placental villi tertiary stem villi:

7. Cytotrophoblastic cell column cytotrophoblastic shell intervillous space free villi anchoring villous

8. Evolution of chorion Chorion leave Chorion frondosum

9. Hydatidiform mole chorioepithelioma Abnormal development

11. Yolk sac Formation and evolution vitelline stalk vitelline ductvitelline duct

12. Meckel’s diverticulum Umbilical fistula Abnormal Development

13. Significance blood island 血岛 earlist hematopoietic organ producing primordial germ cell

14. Amnion Formation and evolution :

16. amniotic fluid

17. Function fetal free movement serves as a protective cushion ① preventing the adhesion of embryo ② absorbing shakes ③ dilating the cervical canal lubricating the delivery tract lubricating the delivery tract

19. Normal volume Abnormal volume Oligohydramnios kidney hypoplasia urethra atresia Polyhydramnios anencephaly esophageal atresia

20. Allantois Formation and evolution: urachus median umbilical ligament Significance allantoic arteries umbilical A allantoic veins umbilical V

21. Abnormal development Urachal fistula urachal diverticulum urachal cyst

22. umbilical cord

23. Formation Structure: Amniotic membrane retrograde allantois retrograde yolk sac body stalk(connective tissue) umbilical A umbilical V

24. Normal Length 40 ～ 60cm D: 2cm40 ～ 60cm D: 2cm Intervillous space Decidual septum Cytotrophoblast shell Spiral artery Decidua basalis Chorion laeve Chorion frondosum

25. Encircling neck Long cord >80cm Abnormalities Related to Umbilical Cord

26. Encircling leg

27.  Short cord: <35cm  may result in premature pull and separation of placenta causing severe bleeding during birth

28. Umbilical Cavity umbilical hernia

30. 2.Placenta Form: maternal surface (cotyledon)

31. Placenta: fetal surface

33. structure Maternal portion: decidua basalis Fetal portion: chorion frondosum blood pool placental septum

34. Intervillous space Decidual septum Cytotrophoblast shell Spiral artery Decidua basalis Chorion laeve Chorion frondosum 3 layers: basal plate decidua basalis cytotrophoblastic shell Villi and intervillous space chorionic plate

35. Intervillous space Placenta septum Free villus chorionic plate basal plate Cytotrophoblastic shell Cytotrophoblastic column

36. Intervillous space Decidual septum Cytotrophoblast shell Spiral artery Decidua basalis Chorion laeve Chorion frondosum Blood circulation of the placenta Maternal circulation: coiled A→ intervillous space→ endometrial venules fetal circulation: umbilical A→capillaries of villus→umbilical V

37. Placental membrane (barrier) syncytial trophoblast cytotrophoblast and its B.M connective tissue in the villus B.M and endothelium of capillary

38. 1.Syncytium 2.cytotrophoblast and its B.M 3.connective tissue 4.B.M and endothelium of capillary 1.Syncytium and its B.M 2. B.M and endothelium of capillary 1.Syncytium 2. B.M 3. endothelium 1.Syncytium 2.cytotrophoblast 3. B.M of trophoblast 4.connective tissue 5.B.M of capillary 6. endothelium of capillary

40. Function of the placenta 1. exchange of metabolic and gaseous products Simple diffusion facilitated diffusion active transport pinocytosis 2. Production of hormones chorionic gonadotropin estrogen progesterone placental lactogen (chorionic somatomammototropin) 3. protection

41. Ⅵ. Twins, Multiple births and Conjoined twins 1.Twins:

42. monozygotic twins dizygotic twins

43. monozygotic twins ① 2 cell stage ② blastocyst stage ③ bilaminar germ disc stage just before the appearance of the primitive streak

44. dizygotic twins

47. 2. Multiple Births

48. 1999 年出生 南京四胞胎 冰、清、玉、洁

50. Multiple births

51. 2008 年 10 月 14 日上午 9 ∶ 30 ，河南省内黄县东庄镇周庄村 27 岁的农村产妇 菅晓静，在县妇幼保健医院顺利剖腹生产下三女两男龙凤五胞胎。五胞胎 体重分别为 2600 克、 2300 克、 2300 克、 2300 克、 2200 克。 2008 年 10 月 14 日上午 9 ∶ 30 ，河南省内黄县东庄镇周庄村 27 岁的农村产妇 菅晓静，在县妇幼保健医院顺利剖腹生产下三女两男龙凤五胞胎。五胞胎 体重分别为 2600 克、 2300 克、 2300 克、 2300 克、 2200 克。

53. Monozygotic ~ Multiple-zygotic ~ mixed ~ Multiple Births

54. 3.Conjoined Twins 胸腹联胎 臀联胎 头联胎 寄生胎 parasite 联胎种类 Omphalo- thoracopagus craniopagus Pygo- pagus Unsymmetric conjoined twins

55. Conjoined Twins