泌尿生殖发生.ppt

泌尿系统和生殖系统的发生,DEVELOPMENT OF UROGENITAL SYSTEM,Key points1.Development of kidney and ureter;2.Septation of cloaca;3.Development of bladder and urethra;4.Malformation of the urinary system;5.Development of gonads;6.Development of genital ducts;7.Malformation of the genital system.,掌握的内容 1肾和输尿管的发生；2泄殖腔的分隔及膀胱和尿道的发生；3多囊肾和脐尿瘘的形成。4原始生殖细胞的发生和迁移；5睾丸和卵巢的发生；6生殖管道的演变；7 隐睾和先天性腹股沟疝的形成。,起源 第三周 间介中胚层(mesoderm)头侧 生肾节（nephrotome）前肾腹、尾侧 生肾索(nephrogenic cord)尿生殖生殖嵴(urogenital ridge)内：生殖腺嵴gonadal ridge 外：中肾嵴(mesonephric ridge)中肾,In the third week the intermediate mesoderm forms nephrotomes in the cervical part and nephrogenic cords in the remain part.Nephrogenic cords include mesonephric ridge and gonadal ridge.,原基生肾节前肾（nephrotome）生肾索中肾、后肾(nephrogenic cord),肾的原基,一、泌尿系统的发生,（一）肾和输尿管的发生 1前肾（pronephros）4周初，在第714体节外的生肾节内发生,由前肾小管(pronephric tubule)+前肾管(pronephric duct)组成。第4周末,前肾退化。,PronephrosCome from nephrotomesStructure a few pairs of pronephric tubules a pair of pronephric ducts Regresses by the end of week 4 of development and are not funcitonal in humans.,2中肾(mesonephros)4周末，1428体节外的生肾索中肾嵴内 80对中肾小管(mesonephric tubule)+1对中肾管（mesonephric duct，Wolffian duct）,中肾小管呈S形 内侧：肾小囊 血管球 肾小体 外侧：通入中肾管,第10周，大部分中肾小管消失；中肾管保留，与泄殖腔接通。,Mesonephros,Come from mesonephric ridgesStructure mesonephric tubules and mesonephric duct(wolffian duct)It is partially transitory and is functional for a short period.,原基 中肾管末端输尿管芽(ureteric bud)生肾索尾段生后肾原基（组织）(metanephrogenic blastema),3后肾(metanephros)和输尿管的发生,输尿管芽（ureteric bud）反复分支，形成 输尿管、肾盂、肾盏、乳头管和集合管。,外周部分分化形成肾的被膜 内侧部分形成肾小管和肾小囊 近端小管头端凹陷形成肾小囊，与背主动脉分支形成的毛细血管形成肾小体；远端小管和集合管接通。,生后肾组织(metanephrogenic tissue),Metanephros begin to form at week 5 and is functional in the fetus at about week 10 of development.,人类的永久肾为后肾，形成后由盆腔内移至腰部。,前肾、中肾、后肾发生示意图,后肾发生示意图,后肾发生示意图,后肾发生示意图,后肾发生示意图,ureteric bud and metanephrogenic tissue ureteric bud:ureter,Renal pelvis,calyx,and collecting tubules et al.metanephrogenic tissue：the capsules of the kidney,renal capsules and renal tubules.renal corpuscle:renal capsule and glomerulusThe end of distal tubule contacts with collecting tubule,two tubules soon communicate.,Matenephros,（二）膀胱和尿道的发生 1泄殖腔的分隔 后肠末端的膨大部分称泄殖腔(cloaca)，人胚第7周，后肠与尿囊间的间充质增生，形成尿直肠隔(urorectal septum)，尿直肠隔向下沿伸与泄殖腔膜会合，将泄殖腔分为背腹两部分：背侧：原始直肠(primary rectum)分化为直肠和肛管上段 腹侧：尿生殖窦(urogenital sinus)分化为膀胱、尿道和阴道前庭,泄殖腔的分隔,CloacaCloaca is formed by dilation of terminal part of hindgut which connects with allantois and is closed by the cloacal membrane.The urorectal septum divides cloaca into urogenital sinus and primary rectum.,2尿生殖窦(urogenital sinus)的分化 上段 膀胱大部。膀胱三角来源于中肾管，尿囊根部参 与膀胱形成。中段 女性尿道大部份 男性尿道的前列腺部和膜部。下部 女性尿道小部份和阴道前庭 男性尿道的海绵 体部。,尿生殖窦的分化,（三）先天畸形 多囊肾、异位肾、马蹄肾、肾缺如、双输尿管、脐尿瘘、膀胱外翻等,(1)多囊肾(polycystic kidney)肾含许多囊泡，可引起肾功能衰竭 集合小管发育异常或与肾单位未接通,(2)异位肾(ectopic kidney)肾未正常上升，常见停留于盆腔。,(3)马蹄肾(horseshoe kidney)两肾未上升，尾端融合，位置低。易发生尿路梗阻或感染。,异位肾,马蹄肾,马蹄肾,(5)双输尿管(double ureter)输尿管芽过早分支（完全或部分）两条输尿管，或输尿管分叉。,(4)肾缺如(renal agenesis)输尿管芽未发生或未能诱导后肾发生，单侧多见。,双输尿管及输尿管分叉,(6)脐尿瘘(urachal fistula)尿囊（脐尿管）未闭锁 尿液可从脐漏出,脐尿瘘,二、生殖系统的发生,原基：间介中胚层分期：未分化期性分化期性分化的决定 自然倾向女性 两次干预男性 生殖腺 睾丸 生殖管道和外生殖器 男性,睾丸决定因子(YSRY蛋白),雄激素,“不一样,就是不一样”,（一）原始生殖细胞的发生和迁移 第1921天，卵黄囊壁的内胚层发生原始生殖细胞（primodial germ cell)。第25天 原始生殖细胞沿背侧肠系膜向生殖腺嵴迁移。第6周 原始生殖细胞进入初级性索。第7周 生殖腺可分辨出睾丸或卵巢。,原始生殖细胞的发生和迁移,（二）生殖腺的发生1未分化性腺的发生 生殖腺嵴表面上皮 初级性索(primary sex cord),2决定性别分化的因素 未分化生殖腺称性腺(gonad),性腺的分化取决于原始生殖细胞是否含有Y染色体。原始生殖细胞核的Y染色体短壁上有性别决定区（sex determining region of the Y,SRY)，其产物为睾丸决定因子（testis-determining factor,TDF)。在TDF的作用下，生殖腺分化 为睾丸。若无TDF表达，则性腺就会自然地分化为卵巢。,初级性索 生精小管索生精小管、直精小管和睾丸网 表面上皮下的间充质 白膜 生精小管之间的间充质睾丸间质,3睾丸的发生 第78周,10周 初级性索退化 次级性索（secondary sex cord)或称皮质索(cortical cord)孤立的细胞团卵泡细胞 原始生殖细胞 卵原细胞原始卵炮,4卵巢的发生,第5个月,卵原细胞分化为初级卵母细胞。,5睾丸和卵巢下降 第78个月 睾丸到达阴囊 第3个月 卵巢到达盆腔,（三）生殖管道的发生,性未分化期 中肾管（Wolffian duct）中肾旁管(Mller duct)中肾旁(paramesonephric duct)管尾端突入尿生殖窦的后壁形成窦结节,2.性分化期,男性中肾管发育成附睾管、输精管和射精管。中肾小管形成睾丸输出小管.中肾旁管退化,B.女性中肾旁管发育成输卵管和子宫。窦结节阴道板阴道中肾管退化,子宫和阴道的形成示意图,3.生殖管道发生的决定因素 雄激素使中肾管发育；支持细胞分泌抗中肾旁管激素。无雄激素和抗中肾旁管激素,中肾旁管发育。,The paramesonephric ducts The cephalic portion becomes the uterine tubes.The fused portion,the uterovaginal canal,becomes the uterus and the upper 1/3 of the vagina.,The mesonephric ducts develop into the epididymis,the ductus deferens,ejaculatory duct,and the seminal vesicles.The ductus efferentes come from mesonephric tubules.,头端:1个生殖结节(genital tubercle)两侧:1对尿生殖褶(urogenital fold)-尿道沟-尿生殖膜 1对阴唇阴囊隆起(labio-scrotal swelling),(1)未分化期(原基),四、外生殖器的发生,(2)性别分化 男性(A)女性(无 A)生殖结节 阴茎 阴蒂尿生殖褶 尿道海绵体部 小阴唇尿生殖沟 阴道前庭阴唇阴囊隆起 阴囊 大阴唇,外生殖器的性别分化,（五）先天畸形,先天性腹股沟疝（Inguinal hernia）,隐睾（Cryptorchidism）,子宫、阴道畸形模式图A.双子宫双阴道B.双子宫单阴道C.中隔子宫D.双角子宫E.阴道闭锁,两性畸形(hermaphroditism),假两性畸形 生殖腺为睾丸（男）或卵巢（女）外生殖器更像相对性别,真两性畸形 有两性性腺 外生殖器呈间性 罕见,真两性畸形,男性假两性畸形:雄激素分泌不足,女性假两性畸形:雄激素分泌过多(肾上腺生殖综合征),男性假两性畸形，外生殖器像女性,女性假两性畸形，体格和外生殖器像男性,雄激素不敏感综合征(androgen insensitivity syndrome)染色体为44+XY 睾丸常在腹股沟部，无精子发生体细胞缺乏雄激素受体,雄激素不敏感综合征,外生殖器呈女性，有女性第二性征，但无输卵管、子宫。,OUTLINEFunctionally the urogenital system can be divided into two entirely different components:the urinary system and the genital system.Embryologically and anatomically,however,they are intimately interwoven.Both systems develop from intermediate mesoderm along the posterior wall of the abdominal cavity,and initially the excretory ducts of both system enter a common cavity,the cloaca.,The kidneys are formed in three types:the pronephros,mesonephros,and metanephros.The pronephros is represented by a few pronephric tubules and pronephric ducts in the neck.The pronephros soon degenerate.However,the pronephric ducts persist and utilized by the next set of kidneys.The mesonephros which form in the thoracic and lumbar regions,is large and characterized by excretory units(nephrons)and its own collecting duct,the mesonephric or wolffian duct.In human it may only function briefly,most of the system disappears.In male,the ducts and a part of tubules of the mesonephros form the conducting ducts for sperm from the testes to the urethra.In female,these ducts and tubules regress.,The metanephros or permanent kidneys appear in the fifth week.The metanephros develop from two sources：ureteric bud(an outgrowth of the mesonephric duct)and metanephrogenic tissue.Metanephrogenic tissue forms renal capsules and renal tubules.And the collecting system originates from the ureteric bud.This bud also gives rise to the ureter,renal pelvis,calyces.Connection between renal tubule and the collecting tubule is important for normal development.,The genital system consists of gonads or primitive sex glands,genital ducts,and external genitalia.All three components go through an indifferentiation stage in which they may develop into either a male or a female.Sex differentiation is a complex process that involves many genes.The key to sexual dimorphism is the Y chromosome,which contains the SRY(sex-determining region on Y)gene on its short arm.The SRY protein is the testis-determining factor;under its influence male development occurs;in its absence female development is established.,The testis-determining factor causes development of the testis.Absence of the testis-determining factor stimulates formation of the ovary.When primordial germ cells fail to reach the indifferent gonad,the gonad remains indifferent or is absent.,There are two types of ducts in the early embryo:a pair of mesonephric ducts and a pair of paramesonephric ducts.In male the mesonephric ducts develop into genital ducts.In female the paramesonephric ducts develop.,QUESTIONS 1.Illustrate the development of kidney.2.Explain the formation of polycystic kidney,horseshoe kidney and double ureter.3.What is cloaca?what organs will it further develop into?4.where do the primordial germ cells migrate from?5.Describe the development of testis and ovary.6.How do the mesonephric ducts and paramesonephric ducts develop in male or female?,