医学课件reproductive

Chapter 12 Reproductive Physiology,Wang Guoqing Department of Physiology, Medical School, Soochow University, Suzhou 215123, China E-mail: TelI. Sexual differentiation and formation of genitalia II. Male reproductive system: function and regulation III. Female reproductive system: function and regulation IV. Pregnancy and parturition V. Mechanism of milk secretion VI. Sex Physiology,What will we discuss in this chapter? (Outline),I. Sexual differentiation and formation of genitalia,1. Sexual Differentiation 性别的分化 Sexual differentiation is determined at three levels: chromosomes, gonads, and phenotype. Males have XY and females have XX chromosomes. Female characteristics develop spontaneously in the absence of the Y chromosome. Y chromosome contains the genesex-determining region (SRY)that is necessary for the development of male characteristics. Gonads are composed of three cell types in both males and females: supporting cells (Sertoli or granulosa cells); stomal cells (Leydig or theca cells); and germ cells (spermatogonia or oocytes). Fetal testes secrete two hormonesantimullerian hormone and testosteronethat are essential for development of the male gonads and internal genitalia; in their absence female gonads and internal genitalia develop. Dihydrotestosterone is responsible for development of male external genitalia.,Human chromosomes 人类染色体,Chromosomes may decide sex 染色体决定性别,2. Formation of internal genitalia 内生殖器的形成,3. Formation of external genitalia 外生殖器的形成,Origin of mammalian life,Puberty 青春期,Onset of puberty is marked by pulsatile secretion of GnRH, FSH, and LH (female, age of 6-8 years and male, age of 9-10 years). In the male, FSH stimulates sperm and Sertoli cell development while LH stimulates Leydig cell proliferation and testosterone secretion. In the female, FSH stimulates follicle development and, along with LH, the synthesis of estradiol. Testosterone and estradiol stimulate the development of secondary sex characteristics and a growth spurt in the male and female, respectively.,Male reproductive system: function and regulation,Testes are composed of seminiferous tubules that produce sperm and Leydig cells, which produce testosterone. Spermatogenesis results from conversion of spermatogonia to mature sperm through mitosis, meiosis, and differentiation. Sertoli cells of the seminiferous tubules support sperm development as well as surround and isolate developing sperm from the blood supply. Leydig cells, under the influence of LH, secrete testosterone. FSH and testosterone acting through Sertoli cells enable spermatogenesis. Blood levels of testosterone and inhibin feed back to regulate pituitary release of FSH and LH.,Maturing sperm come from the testes. 成熟的精子源自睾丸,The testes are composed of maturing sperm (spermatogonia, spermatozoa), Sertoli cells, and Leydig cells that interact to ensure a continuous production of sperm.,Histology of testes 睾丸的组织学,Histology of testes,Testicle tissue under the microscope,Structure of sperm 精子的结构,Male formation,Male main sexual gland Testis 男性主性腺-睾丸,Anatomy of male genitalia,Anatomy of male external genitalia,Endocrine regulation of male reproduction,sperm,III. Female reproductive system: function and regulation,Ovary has three regions: cortex composed of follicles; medulla composed of stromal and hormone-producing cells; and hilum, the point of entry of blood vessels and nerves. Follicles are composed of three cell types: oocytes, granulosa, thecal. Initial development of oocytes beings in fetal life, but maturation is delayed until puberty when single oocytes mature and are released monthly for the next 4 decades. Progesterone and estradiol are main steroid hormones produced by the ovaries estradiol from granulosa cells and progesterone from many cell types. Estradiol is released prior to ovulation, progesterone after ovulation; both prepare the uterus for egg implantation. FSH stimulates monthly development of follicles, LH stimulates monthly ovulation, and both stimulate synthesis and secretion of progesterone and estradiol. Corpus luteum, the postovulation follicle, secretes estradiol and progesterone to sustain the egg and uterus if fertilization and implantation occur.,Anatomy of female genitalia,Anatomy of female genitalia,Female internal genitalia 女性内生殖器,Female main sexual gland Ovary 女性的主性腺-卵巢,Structure of uterine wall 子宫壁的结构,Synthesis of testosterone, progesterone and estradiol,Endocrine regulation of sexual hormone 性激素的内分泌调节,Various sexual hormones changes in early to mid-follicular phase卵泡期,Various sexual hormones changes in early to mid-luteal phase黄体期,Various sexual hormones changes in late follicular phase and ovulation,Various sexual hormones changes in late luteal phase,Mechanism of menstrual cycle induced by the changes in various sexual hormone *,Endometrium,Pregnancy and parturition 1. Pregnancy,Fertilization of the oocyte occurs within 24 hours of ovulation in the distal end of the oviduct. Fertilized egg completes second meiosis and divides repeatedly to form multicelled blastocyst. Blastocyst implants in uterine wall within 5 days of ovulation. After implantation, blastocyst secretes human chorionic gonadotropin (hCG, within 9 days of ovulation), which signals the corpus luteum to continue secreting progesterone and estradiol and is basis of the pregnancy test. Progesterone is produced from cholesterol by the placenta and estriol through the interaction of the placenta and fetal adrenal cortex and liver. Progesterone and estriol support development of the fetus as well as maternal breast development. The mechanism by which parturition is initiated is unclear but involves an interplay between progesterone, prostaglandins, and oxytocin that increase the frequency of uterine contraction.,Effect of the theca and granulose cells of the ovary,The theca and granulose cells of the ovary interact to ensure adequate production of androgens (androstenedione, testosterone) and estradiol.,Precondition of pregnancy is ovum must combine with sperm,Precondition of pregnancy is ovum must combine with sperm to be zygote,The process of zygote Formation 受精卵的形成过程,Ovulation and fecundation 排卵与受精,Growth of fetus (10 weeks),Structure of placenta 胎盘的结构,Synthesis of the major form of estrogenestriol during pregnancy,Ensuring an adequate production of estriol during pregnancy requires exchange of substances between the maternal blood, the placenta, the fetal adrenal gland, and the fetal liver.,2. Parturition 分娩,Parturition,Parturition,Expulsion of the placenta after Parturition,Endocrine mechanism of Parturition 分娩的内分泌机制,V. Mechanism of milk secretion 1. Anatomy of breast 乳房的解剖,Progesterone and estrogen stimulate the development and growth of the mothers breasts. Estrogen also stimulates prolactin secretion by the anterior pituitary, which participates in breast development. At parturition, the breasts are ready for milk production and release induced by increased prolactin and oxytocin levels brought on by suckling.,2. Histology of breast 乳房的组织学,3. Mechanism of milk secretion 泌乳的机制,VI. Sex Physiology,Viripotent representation Changes in physique during puberty (青春期) Genital (生殖器的) development Secondary sexual characters appearance Sex maturation regulation Sexual abnormality during puberty Sexual excitation and sexual behavior Male Female Sexual behavior regulation Nervous regulation Hormonal regulation Sexual dysfunction,Summarization,PLEASE TAKE DOWN,Consideration after class 【本章节问题思考】 1. Please describe testicular sperm formation and its endocrine function. 2. Please describe ovarian ovum formation and its endocrine function. 3. What is mechanisms of menstrual cycle ? 4. Please describe pregnant maintenance and hormonal regulation. 5. What is phenotype of sex maturation ?,Guide of Reference 【本章节学习参考书单】,1. 姚泰主编. 生理学. 第五版. 北京: 人民卫生出版社, 2000. 2. 范少光, 汤浩, 潘伟丰主编. 人体生理学（二版）. 北京: 北京医科大学出版社, 2000. 3. 贺石林, 李俊成, 秦晓群主编. 临床生理学. 北京: 科学出版社, 2001. 4. 王庭槐主编. 生理学. 全国高等学校医学规划教材, 北京: 高等教育出版社, 2005. 5. 陈大元. 受精生物学. 北京: 科学出版社, 2000. 6. 杨刚主编. 内分泌生理与病理生理学. 天津: 天津科学技术出版社, 1996. 7. Greenspan FS, Strewler GJ主编. 施秉银主译. 基础与临床内分泌学. 第五版. 西安: 世界图书出版社, 2001. 8. Kandal ER, Schwartz JH, Jessell T. Principles of neuroscience. 4th ed, New York: McGraw-Hill Co Inc, 2000. 9. Hammond C. Cellular and molecular neurobiology. 2nd ed, London: San Diego: Academic Press, 2001. 10. Berne RM, Levy MN, Koeppen BMI, Stanton BA. Physiology, 5th ed, St Louis: Mosby Electronic Production, 2004. 11. Guyton AC, Hall JE. TEXTBOOK OF MEDICAL PHYSIOLOGY, 10th ed, Phil