组培人体胚胎学

人体胚胎学Human embryology主讲人： 苏衍萍20 Preface 1.Definition:(定义 ) Study development and mechanism of human body from fertilization to birth.2. Content(内容 ) (1) Normal human body development in uterus.(胚胎发育 ) (2)Relation between mother and embryo. (母子关系 ) (3) Hereditary malformation and reproductive engineering(先天畸形与生殖工程 )3、 胚胎分期(1)preembryonic period(胚前期 )fertilization to 2W(2)embryonic period(胚期 )3W 8W (sensitive periodof teratogenesis,致畸敏感期 ) (3)fetal period(胎儿期 )9Wbirth*perinatal period(围产期 )26W- 4W after birth受精 8周末胚期 胎期 围产期（ 1-8周） （ 9-38周） (26周 -生后 4周 )出生受精、卵裂、 器官系统发育、胚泡形成、 功能建立完善、植入 、 胚体长大。三胚层形成分化、胎膜胎盘形成器官原基建立有害因素影响可致畸 4、 Importance and method (1) Importance (2) Study methods21 Human embryogenesis and development of early period1 Germ cell and fertilization(生殖细胞和受精 ) (1) Germ cell (生殖细胞 ) spermatozoon （精子 ） A. Morphological maturation(形态的成熟 ) in testis B.Spermatozoa undergo a Functional maturation in process of journey from the seminiferous tubules （生精小管） to the ampulla of the oviduct （输卵管） C. Capacitation： 获能： Definition :It is defined as the final step of sperm maturation , consisting primarily of changes in the acrosome (顶体） that prepare it to release the enzymes required to penetrate the zona pellucida（ 透明带） . Position :within female genital tract （ 女性生殖管道） and to require contact with the secretions of the oviduct . Sperm survive :13 day Capacity of fertilization :1dayOvum (卵子 ):Character A.Oogenesis(卵细胞的发生） is discontinuous and begins during fetal life. B.The secondary oocyte is arrested at the second meiotic （ 减数分裂） metaphase（ 中期） in ovulation C. Corona radiata（ 放射冠） and zona pellucida（ 透明带） accompanied oocyte D. Oocyte survive :1day Capacity of fertilization :12hours（ 2）受精 fertilization A. Definition(定义 ): It is a process that the spermatozoon（ 精子） successfully. penetrates the oocyte （ 卵母细胞） and forms zygote(受精卵） B.Position(位置 ):the ampulla of the oviduct( 输卵管壶腹部 )C. Time(时间 ):within 12 hours after ovulation(排卵 )or 24 hours after ejaculation(射精 ) D. 条件 （ 1 ） 精卵正常 （ 2 ） 精液质量 3-5ml 次， 400 万个 ml, 畸形 20%,30 min 内液化，活动率 60% （ 1小时）。 （ 3 ） 精子获能 ,卵子在第二次成熟分裂的中期 （ 4 ） 如期相遇 （ 5 ） 生殖道畅通 （ 6 ） 内环境正常 A 内分泌 B 抗精子抗体 C精神状态E.The process of fertilization受精过程 Sperm binds in a human-specific interaction with a zp3(精卵识别 ) Acrosome reaction(顶体反应 ):The acrosome is induced to release degradative (降解 )enzymes that allow the sperm to penetrate（ 穿透） the zona pellucida. The cell membranes of the two cells fuse.(两膜融合 ) Zona reaction(透明带反应 ):Cortical granules release into the perivitelline（ 卵黄周的） space and interact with the zona pellucida. It alters the sperm receptor molecules,causing the zona to become impenetrable by additional spermatozoa. Female and male pronuclei formed(两性原核形成 ) Two pronuclei membranes disappear as both maternal and paternal chromosomes are replicated in preparation for the first cleavage.(两核融合 ) F. Significance of fertilization (受精的意义 ) （ 1 ） Form a new life (形成新个体 ) （ 2 ） Resume 2N quantity of DNA(染色体复常 ) （ 3 ） Decide sex(决定性别 ) TDF and SRY 1980年代中期 ,发现了核型为 46,XX的男性 ,但其 X染色体上有很小一段 Y染色体短臂上转移来的片段 .因此 1990年揭示了这一片段上存在性别决定区域（ sex determination region of Y chromosome ,SRY)。目前发现包括至少 6个基因参与了胚胎的性别决定。表达产物为 TDF（ testis determination factor) （ 4 ） Heredity and variation(遗传与变异)2.Blastocyst formedand implantation( 胚泡形成与植入） (1) Zygote cleavage（ 卵裂）l Within 24 hours after fertilization, the zygote embarks on a regulated series of mitotic cell divisions called cleavage. The divisions are not accompanied by cell growth, so the subdivide the large zygote into many smaller daughter cells called blastomeres（ 卵裂球） . 24hours 2 blastomeres 40hours 4 blstomeres 3days 612cells 4days 16-32cells (2)Morula（ 桑葚胚） : by the 32 cell stage, the embryo has the appearance of a small mulberry and is therefore,called a morula. 12-16细胞时叫做桑葚胚 The segregation of blastomeres into embryoblast and trophoblast precursors occurs in the morula. 二、卵裂 cleavage （ 一）定义 卵裂球 blastomere （ 二）特点 1 在透明带内 桑椹胚 morula 2 全能性 3 不同步 4 向宫腔运行途中 Blastomere morula (3)胚泡（ blastocyst） The morula develops a fluid-filled cavity and is transformed into a blastocyst胚端滋养层Polar trophoblast内细胞群 inner cell mass胚泡腔 blastocoele滋养层 trophoblast (4)植入 implantation A. Definition: B.Time:5-6 day to 11-12day C.condition (条件 ) 1胚泡发育与子宫内膜同步 2 透明带准时脱落 3宫腔的正常内环境 4 母体内分泌正常 D.Process The blastocyst hatches from the zona pellucida before implanting E.位置 子宫底和体 ,最多见后壁的中上份 F.异常植入 宫外孕 前置胎盘 3、植入后的变化 （一）子宫内膜的变化 蜕膜 decidua 蜕膜反应 decidual response （二）分部 基蜕膜 decidua basalis 包蜕膜 decidua capsularis 壁蜕膜 decidua parietalis 4.Clinical applications (1)Chromosomal abnormalities result in spontaneous abortion or abnormal development It is estimated that one third of all conceptions （ 孕体） in normal, healthy women abort spontaneously;approximately one fourth of these occur before pregnancy is detected. Chromosomal anomalies appear to cause about 40 to 50 per