1、人体胚胎学人体胚胎学Human Human embryologyembryology 泰山医学院泰山医学院20 Preface1.Definition:(定义定义)Study development and mechanism of human body from fertilization to birth.2.Content(内容内容)(1)Normal human body development in uterus.(胚胎发育胚胎发育)(2)Relation between mother and embryo.(母子关系)(3)Hereditary malformation and r
2、eproductive engineering(先天畸形与生殖工先天畸形与生殖工程程)3 3、胚胎分期胚胎分期 (1)1)embryonic period(胚期胚期)1W1W8 8W W(sensitive period of teratogenesis,致畸敏感期致畸敏感期)(2)2)fetal period(胎儿期胎儿期)9Wbirth *perinatal period(围产期围产期)26W-4W after birth 受精受精8周末周末 胚期胚期 胎期胎期 围产期围产期 （1-8周）周）（9-38周）周）(26周周-生后生后4周周)出生出生 受精、卵裂、受精、卵裂、器官系统发育、器官
3、系统发育、胚泡形成、胚泡形成、功能建立完善、功能建立完善、植入植入、胚体长大。胚体长大。三胚层形成分化、三胚层形成分化、胎膜胎盘形成胎膜胎盘形成 器官原基建立器官原基建立有害因有害因素影响素影响可致畸可致畸4 4、Importance and method(1)Importance(2)Study methods21 Human embryogenesis and development of early period1 Germ cell and fertilization(生殖细胞和受精生殖细胞和受精)(1)Germ cell(生殖细胞生殖细胞)spermatozoon（精子（精子）A.M
4、orphological maturation(形态的成熟形态的成熟)in testisB.Spermatozoa undergo a Functional maturation in process of journey from the seminiferous tubules（生精小管）（生精小管）to the ampulla of the oviduct（输卵管）（输卵管）C.Capacitation：获能：获能：Definition:It is defined as the final step of sperm maturation,consisting primarily of
5、changes in the acrosome(顶体）顶体）that prepare it to release the enzymes required to penetrate the zona pellucida（透明带）透明带）.Position:within female genital tract（女性生殖管道）女性生殖管道）and to require contact with the secretions of the oviduct.Sperm survive:13 dayCapacity of fertilization:1dayOvum(卵子卵子):CharacterA.
6、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 ovulationC.Corona radiata（放射冠）and zona pellucida（透明带）accompanied oocyteD.Oocyte survive:1day Capacity of fertilization:12hours（2 2）受精）受精 fertilizationfertiliza
7、tionA.Definition(A.Definition(定义定义):):It is a process that It is a process that the spermatozoonthe spermatozoon（精子）精子）successfullysuccessfully.penetrates the penetrates the oocyteoocyte （卵母细胞）卵母细胞）and and forms zygote(forms zygote(受精卵）受精卵）B.PositionB.Position(位置位置):the):the ampullaampulla of the of
8、 the oviductoviduct(输卵管壶腹部输卵管壶腹部)C.Time(C.Time(时间时间):within 12 hours after):within 12 hours after ovulationovulation(排卵排卵)or 24 hours after or 24 hours after ejaculationejaculation(射精射精)D.D.条件条件（1）精卵正常精卵正常（2）精液质量精液质量 3-53-5mlml 次，次，400400万个万个ml,ml,畸形畸形20%,3020%,30min min 内液化，活动率内液化，活动率 60%60%（1 1小时）
9、。小时）。（3）精子获能精子获能,卵子在第二次成熟分裂卵子在第二次成熟分裂的中期的中期（4）如期相遇如期相遇（5）生殖道畅通生殖道畅通（6）内环境正常内环境正常 A A 内分泌内分泌 B B 抗精子抗体抗精子抗体 C精神状态精神状态E.The process of fertilization受精过程 Sperm binds in a human-specific interaction with a zp3(精卵识别精卵识别)Acrosome reaction(顶体反应顶体反应):The acrosome is induced to release degradative(降解)enzymes
10、 that allow the sperm to penetrate（穿透）the zona pellucida.The cell membranes of the two cells fuse.(两膜两膜融合融合)Zona reaction(透明带反应透明带反应):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 imp
11、enetrable by additional spermatozoa.Female and male pronuclei formed(两性原核形两性原核形成成)Two pronuclei membranes disappear as both maternal and paternal chromosomes are replicated in preparation for the first cleavage.(两核融合两核融合)F.F.Significance of fertilization(受精的意受精的意义义)（1）Form a new life(形成新个体形成新个体)（2）R
12、esume 2N quantity of DNA(染色染色体复常体复常)（3）Decide sex(决定性别决定性别)TDF and SRYTDF and SRY19801980年代中期年代中期,发现了核型为发现了核型为46,XX46,XX的男性的男性,但其但其X X染色体上有很小一段染色体上有很小一段Y Y染色体短臂上染色体短臂上转移来的片段转移来的片段.因此因此19901990年揭示了这一片段年揭示了这一片段上存在性别决定区域（上存在性别决定区域（sex sex determination region of Y chromosome,SRY)。目前发现。目前发现包括至少包括至少6 6个基
13、因参与了胚胎的性别决定。个基因参与了胚胎的性别决定。表达产物为表达产物为TDF（testis determination factor)（4）Heredity and variation(遗传与变异遗传与变异)2.Blastocyst formed and implantation(胚泡形成与植入）(1)Zygote cleavage（卵裂）lWithin 24 hours after fertilization,the zygote embarks on a regulated series of mitotic cell divisions called cleavage.The divi
14、sions 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 blstomeres3days 612cells4days 16-32cells(2)Morula（桑葚胚）:by the 32 cell stage,the embryo has the appearance of a small mulberry and is the
15、refore,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、卵裂二、卵裂cleavage（一）定义 卵裂球卵裂球 blastomere（二）特点1 在透明带内 桑椹胚桑椹胚morula2 全能性3 不同步4 向宫腔运行途中 Blastomere morula(3)胚泡（胚泡（blastocyst）The morula develops a fluid-filled cavity and i
16、s 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)(4)植入植入implantation A.Definition:A.Definition:B.Time:B.Time:5-6 5-6 day to 11-12day day to 11-12day C.condition(C.condition(条件条件)1胚泡发育与子宫内膜同步胚泡发育与子宫内膜同步2 2 透明带准时脱落透明带准时脱落3宫腔的正常内环境宫腔的正常内环境4 母体内分泌正常
17、母体内分泌正常D.ProcessThe blastocyst hatches from the zona pellucida before implantingE.E.位置位置 子宫底和体子宫底和体,最多见后壁的中上份最多见后壁的中上份F.F.异常植入异常植入 宫外孕宫外孕 前置胎盘前置胎盘3 3、植入后的变化、植入后的变化（一）子宫内膜的变化（一）子宫内膜的变化 蜕膜蜕膜 deciduadecidua蜕膜反应蜕膜反应 decidualdecidual response response（二）分部（二）分部基蜕膜基蜕膜deciduadecidua basalisbasalis包蜕膜包蜕膜dec
18、iduadecidua capsulariscapsularis壁蜕膜壁蜕膜deciduadecidua parietalisparietalis4.4.Clinical applicationsClinical applications(1)Chromosomal abnormalities result(1)Chromosomal abnormalities result in spontaneous abortion or abnormal in spontaneous abortion or abnormal developmentdevelopment It is estimated
19、 that one third of all It is estimated that one third of all conceptionsconceptions （孕体）孕体）in normal,healthy in normal,healthy women abort spontaneously;approximately one women abort spontaneously;approximately one fourth of these occur before pregnancy is fourth of these occur before pregnancy is d
20、etected.Chromosomal anomalies appear to detected.Chromosomal anomalies appear to cause about 40 to 50 percent of spontaneous cause about 40 to 50 percent of spontaneous abortions in cases on which the abortions in cases on which the conceptusconceptus has been recovered and examined.has been recover
21、ed and examined.CauseMany chromosomal anomalies arise during gametogenesis and cleavageDown syndrome is an example of a disorder caused by an error during meiosis or mitosisChromosome analysis can determine the parental source and the defective chromosome and provides a basis for diagnosis an possib
22、le treatment (2)Contraceptive techniques interfere with a wide variety of reproductive mechanisms受精与节育和不孕不育受精与节育和不孕不育Despite the high rate of spontaneous abortion,human reproductive efficiency is very high.Methods:（1）Barrier contraceptives prevent the sperm from reaching the egg.(2)The birth control
23、 pill prevent ovulation.(3)injected or implanted sources of progestin deliver a chronic antiovulatory dose.（(4)Nonmedicated IUDs may interfere with conception through effects on both sperm and egg.(5)The antiprogesterone compound RU-486 is an abortifacient.(6)sterilization is used by about one third
24、 of american couples.(7)new methods of contraception are needed.Infertile(15%-30%in American)The maturation of human gametes and early embryos can now be supported outside the body to assist infertile couples.An oocyte can be fertilized in vitro and then implanted in the uterus.In vitro fertilization and embryo transfer(IVF).Gametes or zygotes can be introduced directly into the ampulla of the oviduct.Experimental principles
