1、 业精于勤荒于嬉 行成于思毁于随 【医学生物PPT，欢迎收藏分享】豆丁网友 1中国医科大学中国医科大学基础医学院基础医学院组胚组胚英文教学组英文教学组The process that the mature follicle ruptures and the secondary oocyte, zona pellucida, corona radiata and follicular fluid are released from the ovary is called . Time ovulation takes place at about the middle of the cycleTh
2、e fate of the secondary oocyte FATE 1FATE 2After ovulation, granulosa cells remaining in the wall of the ruptured follicle, together with cells from the theca interna, are vascularized by surrounding vessels. Under the influence of LH, these cells develop a yellowish pigment and change into luteal c
3、ells, which form the corpus luteumCorpus LuteumGRANULOSA LUTEIN CELLSTHECA LUTEIN CELLSCells of corpus luteum Granulosa lutein C： progesterone and relaxin Theca lutein C：estrogenProgesterone, together with estrogen, causes the uterine mucosa to enter the progestational or secretory stage in preparat
4、ion for implantation of the embryo.Relation of fimbriae and ovary. Fimbriae collect the oocyte and sweep it into the uterine tube.Fertilization-Fertilization is the process in which the male and female gametes (sperm and ovum) unite to give rise to a zygote.-place: in the ampulla of the uterine tube
5、Conditions of fertilization: 1) maturation of oocyte 2) maturation of spermatozoa: 2-3 weeks in the ductus epididymis acquire some motilitydecapacitation factor: exist in epididymis, to inhibit the release of acrosome enzymes capacitation factor: secreted by epi. cells of oviduct, capacity of releas
6、ing acrosome enzymescapacitation of spermatozoa 3)quality and quantity of spermatozoa: normal: 3-4 ml, 100,000,000/ml, abnormal: 1.5 ml; or 30%; mobility 70% 4) meeting of sperm and ovum sperm: 4 days ovum: 2 daysprocesses of fertilization: 1) acrosome reaction: A. hyaluronic acidase: dissolve coron
7、a radiata B. interact with ZP3(receptor glycoprotein, exist in zona pellucida) molecules, release acrosin: dissolve zona pellucida then some spermatozoa enter perivitelline space 2) only one spermatozoon fuse with membrane of the ovum: nucleus enter cytoplasm of the ovum cortical reaction: cortical
8、granules (located in cytoplasm of ovum) are released into perivitelline space, and cause zona reaction: change of ZP3 molecules in zona pellucide3) formation of zygote (fertilized ovum) A. secondary meiosis complete: form second polar body B. male pronucleus fuse with female pronucleus to restore 2N
9、 chromosomessignificance of fertilization:1) a new life begin(initiation of cleavage)2) restoration of the diploid number of chromosomes3) determination of the sex of the new individual: ovum(22+X) + X-bearing spermatozoon = girl ovum(22+X) + Y-bearing spermatozoon = boyBlastocyst formation and impl
10、antation 2-cell stage8-cell stage4-cell stage morula Early blastocystLate blastocyst1) cleavage and blastocyst formationcleavage: mitosis of the zygote-blastomere: cells from cleavage 30h: 2 cells 40h: 4 cells 72h: 12-16 cells morula formationformation of blastocyst: by 5th day, blastomere reach to
11、107, small space appear between themblastocoele: filled with liquidtrophoblastinner cell mass (embryoblast )polar trophoblastinner cell massblastocoeletrophoblastZona pellucidaPolar trophoblastEarly blastocystlate blastocyst 2) Implantationdefinition: the process in which the blastocyst is embedded
12、in endometrium of the uterustime: begin on the 5th 6th day; finish on the 11th 12th day place: fundus and body of uterus process: zona pellucide disappear polar trophoblast touch the e n d o m e t r i u m s e c r e t e proteolytase dissolve the endothelium embedded into endometrium coagulation plug
13、seal the space* trophoblast become into two layers when blastocyst is embedding into endometrium syncytiotrophoblast cytotrophoblastendometriumColumnar epitheliumA 7.5-day human blastocyst, partially embedded in the endometrial stroma.The trophoblast consists of an inner layer with mononuclear cells
14、, the cytotrophoblast,and an outer layer without distinct cell boundaries, the syncytiotrophoblast. The embryoblast is formed by the ectoderm and endoderm. The amniotic cavity appears as a small cleft.ectodermendodermdecidual response of endometrium stroma cell predecidual cell decidual cell (cell b
15、ecome larger and rich in glycogen and lipid droplets)endometrium decidua: decidua basalis decidua capsularis decidua parietalisConditions of implantation: - endometrium is in secretory phase - morula reach the cavity of uterus on time - zona pellucide disappears in timeRelationship between the embryo and the endometriumDecidua capsularisembryovaginacervixUterine cavityDecidua parietalisDecidua basalis
