DOCSLIB.ORG

Female Genital System

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Female Genital System Module A Female Genital System Martin Špaček Histology and Embryology • Pictures from: • Junqueira et al.: Basic histology • Rarey, Romrell: Clinical human embryology • Sadler: Langman’s medical embryology • Young, Heath: Wheather’s functional histology • http://www.med.unc.edu/embryo_images Female Genital System Development • Development of the indifferent stages – see presentation “Male genital system” http://www.lf3.cuni.cz/histologie Development of the Ovary • Absence of TDF (testis-determining factor) • Primitive sex cords degenerate Development of the Ovary • Surface epithelium gives rise to a second generation of cords – cortical cords • Epithelial cells surrounding the germ cells form the follicular cells Development of the Genital Ducts • Absence of MIS (Müllerian inhibiting substance) in the female • Regression of the mesonephric (Wolffian) ducts Development of the Genital Ducts • Paramesonephric (Müllerian) ducts: – cranial ends → uterine tubes – caudal segments → uterus, upper part of the vagina Development of the Genital Ducts • Vagina develops from: – caudal segments of the paramesonephric ducts – vaginal plate Development of the Genital Ducts • Abnormalities of the uterus and vagina – lack of fusion of the paramesonephric ducts – or the atresia Development of the Genital Ducts • Remnants of the mesonephric tubules and ducts – epoophron, paroophron, Gartner’s canal External Genitalia in the Female • indiferent stage • female genital – absence of testosterone • genital tubercle • clitoris • urogenital folds • labia minora • genital swellings • labia majora Female Pseudohermaphroditism Adrenogenital syndrome masculinization of the external genitalia caused by excessive production of androgens by the adrenals 46, XX: Histology of the Female Genital System •Ovary • Uterine tube • Uterus (Womb) •Vagina • External genitalia Ovary Cortical region simple squamous or cuboidal epithelium (germinal epithelium) tunica albuginea loose connective tissue, fibroblasts ovarian follicles Medullary region loose connective tissue, vessels Ovarian Follicles Primordial Follicles Oocyte spherical cell with large nucleus Single layer of flattened follicular cells Primary Follicles Follicular cells cuboidal, single → stratified epithelium = granulosa layer Zona pellucida surrounds oocyte (glycoproteins) Theca folliculi differentiating stroma around the follicle Secondary (vesicular) Follicle Cavities between the cells → antrum Theca differentiates into two layers: theca interna – produce androstendion theca externa Mature Follicle (Graafian) Measures about 2 cm in diameter Cumulus oophorus cluster of follicular cells between the oocyte and the wall of the follicle Corona radiata single layer of follicular cells around the oocyte Ovulation Rupture of the mature follicle Oocyte with the zona pellucida and the corona radiata is released Oocyte enters the uterine tube Slide G1 – Ovary HE Slide G1 – Ovary HE Slide G1 – Ovary HE SlideSlide G3G3 –– OvaryOvary (rabbit)(rabbit) HEHE Corpus Luteum After ovulation the granulosa cells and the theca interna transform into a corpus luteum Corpus luteum of menstruation (lasts 14 days) Corpus luteum of pregnancy (stimulated by hCG) Corpus albicans Corpus Luteum Invasion of blood vessels, connective tissue Granulosa lutein cells and theca lutein cells produce progesteron and estrogens SlideSlide G2G2 –– CorpusCorpus LuteumLuteum HEHE SlideSlide G2G2 –– CorpusCorpus LuteumLuteum HEHE Oviducts (Fallopian or Uterine Tube) Mucosa mucosal folds simple columnar epithelium – ciliated and secretory cells lamina propria Muscular layer inner circular outer longitudinal Serosa layer = visceral peritoneum SlideSlide G4G4 –– uterineuterine tubetube ((isthmusisthmus)) SlideSlide G5G5 –– uterineuterine tubetube ((ampullaampulla)) SlideSlide G5G5 –– uterineuterine tubetube ((ampullaampulla)) SlideSlide G5G5 –– uterineuterine tubetube ((ampullaampulla)) Uterus Endometrium (mucosa) simple columnar epithelium with ciliated and secretory cells lamina propria – simple tubular glands functionally basal layer and functional layer Myometrium thick smooth muscle layer Adventitia or serosa Menstrual Cycle The menstrual phase (the 1st to the 4th day) The proliferative phase (the 5th to the 14th day) Secretory (luteal) phase (the 15th to the 28th day) Menstrual Phase Corpus luteum ceases function → drop of the levels of progesterone and estrogens Ischemia Necrosis of the functionalis layer Bleeding Proliferative Phase Estrogenic or follicular phase Proliferation of the cells Glands straight and narrow Secretory Phase Depends on the progesterone secreted by the corpus luteum Endometrial glands initiate their secretory activity Glands become highly coiled SlideSlide G6G6 –– fundusfundus uteriuteri HEHE SlideSlide G6G6 –– fundusfundus uteriuteri HEHE Uterine Cervix Endocervix simple columnar epithelium cervical glands (may become obstructed → nabothian cysts) Ectocervix external segment that bulges into the vagina stratified squamous epithelium Uterine Cervix Transformation zone abrupt epithelial transition between the endocervix and the ectocervix dysplasia, carcinoma in situ, invasive carcinoma Papanicolaou Smear • Cytologic analysis of smears of the cervical epithelium • Can detect dysplasia and carcinoma in situ SlideSlide G7G7 –– cervixcervix uteriuteri HEHE Vagina • Mucosa layer – stratified squamous epithelium • accumulate glycogen (→ lactic acide) – lamina propria (devoid of glands) • Muscular layer – mainly longitudinal smooth muscle • Adventitial layer – dense connective tissue, rich in elastic fibers SlideSlide G9G9 –– VVaginaagina ((PASPAS++HH)) SlideSlide G9G9 –– VVaginaagina ((PASPAS++HH)) SlideSlide G10G10 –– VVaginaagina HEHE SlideSlide G10G10 –– VVaginaagina HEHE External Genitalia • Modified skin structures – (keratinized) stratified squamous epithelium •Monspubis • Labia majora – adipose tissue, hair – apocrine sweat glands and sebaceous glands • Labia minora – skin folds without adipose tissue • Clitoris – two erectile bodies.
Load more

Recommended publications
  • Male Reproductive System Sexual Reproduction Requires Two Types Of
    Male Reproductive system Sexual reproduction requires two types of gametes or sex cells. In the male these cells are the spermatozoa and in the female they are the ova. The reproductive systems are unique in three respects 1. They are specialized in perpetuating the species and passing genetic information. 2. The anatomy and physiology between the male and female reproductive systems are different. 3. They exhibit latent development under hormonal control. The structures of the male reproductive system can be divided into three categories. 1. Primary sex organs - the gonads (testes). These produce sperm and sex hormones. 2. Secondary sex organs - the structures necessary for caring for and transportation of the sperm. A. Sperm transporting ducts 1. epididymus 2. ductus deferens 3. ejaculatory ducts 4. urethra B. Accessory glands 1. seminal vesicle 2. prostate gland 3. bulbourethral (Cowper's) glands C. Copulatory organ - penis. Also includes the scrotum (the skin enclosing the testes) 3. Secondary sex characteristics - These are not reproductively necessary, but are considered sexual attractants. They include things such as body hair, body physique, and voice pitch. Sexual determination - Sex is determined at the time of conception. As we will see, all ova have an x chromosome and sperm are 50:50 X and Y. If an ova is fertilized by an x sperm then we have a female. If an ova is fertilized by a Y sperm then we have a male. Sometimes we see more than one X in an ovum. As long as there is a Y chromosome we will have a male. ie. XXXY = male.
    [Show full text]
  • Mechanisms of Gonadal Morphogenesis Are Not Conserved Between Chick and Mouse ⁎ Ryohei Sekido , Robin Lovell-Badge
    Developmental Biology 302 (2007) 132–142 www.elsevier.com/locate/ydbio Mechanisms of gonadal morphogenesis are not conserved between chick and mouse ⁎ Ryohei Sekido , Robin Lovell-Badge Division of Developmental Genetics, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK Received for publication 3 June 2006; revised 16 August 2006; accepted 5 September 2006 Available online 9 September 2006 Abstract To understand mechanisms of sex determination, it is important to know the lineage relationships of cells comprising the gonads. For example, in mice, the Y-linked gene Sry triggers differentiation of Sertoli cells from a cell population originating in the coelomic epithelium overlying the nascent gonad that also gives rise to uncharacterised interstitial cells. In contrast, little is known about origins of somatic cell types in the chick testis, where there is no Sry gene and sex determination depends on a ZZ male/ZW female mechanism. To investigate this, we performed fate mapping experiments in ovo, labelling at indifferent stages the coelomic epithelium by electroporation with a lacZ reporter gene and the underlying nephrogenous (or mesonephric) mesenchyme with chemical dyes. After sex differentiation, LacZ-positive cells were exclusively outside testis cords and were 3βHSD-negative, indicating that the coelomic epithelium contributes only to non-steroidogenic interstitial cells. However, we detected dye-labelled cells both inside and outside the cords. The former were AMH-positive while some of the latter were 3βHSD- positive, showing that nephrogenous mesenchyme contributes to both Sertoli cells and steroidogenic cells. This is the first demonstration via lineage analysis that steroidogenic cells originate from nephrogenous mesenchyme, but the revelation that Sertoli cells have different origins between chick and mouse suggests that, during evolution, mechanisms of gonad morphogenesis may diverge alongside those of sex determination.
    [Show full text]
  • ANA214: Systemic Embryology
    ANA214: Systemic Embryology ISHOLA, Azeez Olakune [email protected] Anatomy Department, College of Medicine and Health Sciences Outline • Organogenesis foundation • Urogenital system • Respiratory System • Kidney • Larynx • Ureter • Trachea & Bronchi • Urinary bladder • Lungs • Male urethra • Female urethra • Cardiovascular System • Prostate • Heart • Uterus and uterine tubes • Blood vessels • Vagina • Fetal Circulation • External genitalia • Changes in Circulation at Birth • Testes • Gastrointestinal System • Ovary • Mouth • Nervous System • Pharynx • Neurulation • GI Tract • Neural crests • Liver, Spleen, Pancreas Segmentation of Mesoderm • Start by 17th day • Under the influence of notochord • Cells close to midline proliferate – PARAXIAL MESODERM • Lateral cells remain thin – LATERAL PLATE MESODERM • Somatic/Parietal mesoderm – close to amnion • Visceral/Splanchnic mesoderm – close to yolk sac • Intermediate mesoderm connects paraxial and lateral mesoderm Paraxial Mesoderm • Paraxial mesoderm organized into segments – SOMITOMERES • Occurs in craniocaudal sequence and start from occipital region • 1st developed by day 20 (3 pairs per day) – 5th week • Gives axial skeleton Intermediate Mesoderm • Differentiate into Urogenital structures • Pronephros, mesonephros Lateral Plate Mesoderm • Parietal mesoderm + ectoderm = lateral body wall folds • Dermis of skin • Bones + CT of limb + sternum • Visceral Mesoderm + endoderm = wall of gut tube • Parietal mesoderm surrounding cavity = pleura, peritoneal and pericardial cavity • Blood &
    [Show full text]
  • Actinomycosis Israeli, 129, 352, 391 Types Of, 691 Addison's Disease, Premature Ovarian Failure In, 742
    Index Abattoirs, tumor surveys on animals from, 823, Abruptio placentae, etiology of, 667 828 Abscess( es) Abdomen from endometritis, 249 ectopic pregnancy in, 6 5 1 in leiomyomata, 305 endometriosis of, 405 ovarian, 352, 387, 388-391 enlargement of, from intravenous tuboovarian, 347, 349, 360, 388-390 leiomyomatosis, 309 Acantholysis, of vulva, 26 Abdominal ostium, 6 Acatalasemia, prenatal diagnosis of, 714 Abortion, 691-697 Accessory ovary, 366 actinomycosis following, 129 Acetic acid, use in cervical colposcopy, 166-167 as choriocarcinoma precursor, 708 "Acetic acid test," in colposcopy, 167 criminal, 695 N-Aceryl-a-D-glucosamidase, in prenatal diagnosis, definition of, 691 718 of ectopic pregnancy, 650-653 Acid lipase, in prenatal diagnosis, 718 endometrial biopsy for, 246-247 Acid phosphatase in endometrial epithelium, 238, endometritis following, 250-252, 254 240 fetal abnormalities in, 655 in prenatal diagnosis, 716 habitual, 694-695 Acridine orange fluorescence test, for cervical from herpesvirus infections, 128 neoplasia, 168 of hydatidiform mole, 699-700 Acrochordon, of vulva, 31 induced, 695-697 Actinomycin D from leiomyomata, 300, 737 in therapy of missed, 695, 702 choriocarcinoma, 709 tissue studies of, 789-794 dysgerminomas, 53 7 monosomy X and, 433 endodermal sinus tumors, 545 after radiation for cervical cancer, 188 Actinomycosis, 25 spontaneous, 691-694 of cervix, 129, 130 pathologic ova in, 702 of endometrium, 257 preceding choriocarcinoma, 705 of fallopian tube, 352 tissue studies of, 789-794 of ovary, 390, 391 threatened,
    [Show full text]
  • Testicular Tumors: General Considerations
    TESTICULAR TUMORS: 1 GENERAL CONSIDERATIONS Since the last quarter of the 20th century, EMBRYOLOGY, ANATOMY, great advances have been made in the feld of HISTOLOGY, AND PHYSIOLOGY testicular oncology. There is now effective treat- Several thorough reviews of the embryology ment for almost all testicular germ cell tumors (22–31), anatomy (22,25,32,33), and histology (which constitute the great majority of testicular (34–36) of the testis may be consulted for more neoplasms); prior to this era, seminoma was the detailed information about these topics. only histologic type of testicular tumor that Embryology could be effectively treated after metastases had developed. The studies of Skakkebaek and his The primordial and undifferentiated gonad is associates (1–9) established that most germ cell frst detectable at about 4 weeks of gestational tumors arise from morphologically distinctive, age when paired thickenings are identifed at intratubular malignant germ cells. These works either side of the midline, between the mes- support a common pathway for the different enteric root and the mesonephros (fg. 1-1, types of germ cell tumors and reaffrms the ap- left). Genes that promote cellular proliferation proach to nomenclature of the World Health or impede apoptosis play a role in the initial Organization (WHO) (10). We advocate the use development of these gonadal ridges, includ- of a modifed version of the WHO classifcation ing NR5A1 (SF-1), WT1, LHX1, IGFLR1, LHX9, of testicular germ cell tumors so that meaningful CBX2, and EMX2 (31). At the maximum point comparisons of clinical investigations can be of their development, the gonadal, or genital, made between different institutions.
    [Show full text]
  • 1- Development of Female Genital System
    Development of female genital systems Reproductive block …………………………………………………………………. Objectives : ✓ Describe the development of gonads (indifferent& different stages) ✓ Describe the development of the female gonad (ovary). ✓ Describe the development of the internal genital organs (uterine tubes, uterus & vagina). ✓ Describe the development of the external genitalia. ✓ List the main congenital anomalies. Resources : ✓ 435 embryology (males & females) lectures. ✓ BRS embryology Book. ✓ The Developing Human Clinically Oriented Embryology book. Color Index: ✓ EXTRA ✓ Important ✓ Day, Week, Month Team leaders : Afnan AlMalki & Helmi M AlSwerki. Helpful video Focus on female genital system INTRODUCTION Sex Determination - Chromosomal and genetic sex is established at fertilization and depends upon the presence of Y or X chromosome of the sperm. - Development of female phenotype requires two X chromosomes. - The type of sex chromosomes complex established at fertilization determine the type of gonad differentiated from the indifferent gonad - The Y chromosome has testis determining factor (TDF) testis determining factor. One of the important result of fertilization is sex determination. - The primary female sexual differentiation is determined by the presence of the X chromosome , and the absence of Y chromosome and does not depend on hormonal effect. - The type of gonad determines the type of sexual differentiation in the Sexual Ducts and External Genitalia. - The Female reproductive system development comprises of : Gonad (Ovary) , Genital Ducts ( Both male and female embryo have two pair of genital ducts , They do not depend on ovaries or hormones ) and External genitalia. DEVELOPMENT OF THE GONADS (ovaries) - Is Derived From Three Sources (Male Slides) 1. Mesothelium 2. Mesenchyme 3. Primordial Germ cells (mesodermal epithelium ) lining underlying embryonic appear among the Endodermal the posterior abdominal wall connective tissue cell s in the wall of the yolk sac).
    [Show full text]
  • Sex Determination
    Sex Determination • Most animal species are dioecious – 2 sexes with different gonads • Females: produce eggs in ovaries • Males: produce sperm in testes • Exception • Hermaphrodites: have both types of gonads • Many animals also differ in secondary traits What Determines Sex? • Individual differentiates into male or female • Causes – Genetic factors (sex chromosomes) – occur at fertilization – Environmental factors – occur after fertilization How Do Vertebrate Gonads Develop? • Gonad differentiation – first morphological difference between males and females • Gonads develop from intermediate mesoderm • Paired structures What is a Bipotential Gonad? • Indifferent gonad develops – 4-6 wks in human = “bipotential stage” – genital ridge forms next to developing kidney (mesonephric ridge) Structure of the Indifferent Gonad • Sex cords form – Columns of epithelial cells penetrate mesenchyme – Primordial germ cells migrate from posterior endoderm – Become surrounded by sex cords What is the Fate of the Sex Cords? • Initially in central area (medulla, medullary) – Will develop in male – Proliferate • In outer area (cortex, cortical) – Develop in female • Normally binary choice Differentiation of the Gonad • Into testes or ovaries – primary sex determination – does not involve hormones network of internal sex cords (at new cortical sex cords puberty: --> seminiferous tubules, cluster around each germ cell Sertoli cells Male Differentiation • Male sex cords or testis cords proliferate and cortex becomes thick layer of extracellular matrix • Male
    [Show full text]
  • Animal and Veterinary Science Department University of Idaho
    Animal and Veterinary Science Department University of Idaho EMBRYOGENESIS AND SEXUAL DIFFFERENTIATION AVS 222 (Instructor: Dr. Amin Ahmadzadeh) Chapter 4 I. DIFFERENTIATION Primitive group of unspecialized cells develop a functional and specialized group of cells that provide a common function A. Involves Formation of Three Germ Layers 1. Embryonic tissue, which form all adult tissues and organs B. Germ Layers Formed During Gastrulation (re-arrangement of the embryonic cells) C. Three Germ Layers: (Table 4-1) 1. Ectoderm: in general, form exterior tissues (Figure 4-1, adapted from Senger ©) a. Skin, hair, sweat glands b. Mammary glands c. Hypothalamus, anterior and posterior pituitary d. Part of the reproductive tract (male and female) 2. Mesoderm: in general, forms structural tissue (Figure 4-1) a. Muscle, Skeletal system, blood vessels b. Reproductive system gonads, uterus, cervix, part of vagina, accessory sex glands e. Renal system 3. Endoderm: in general, form internal organs (Figure 4-1) a. Digestive system, Liver, lungs b. Majority of glands II. SEXUAL DIFFERENTIATION AND DETERMINATION A. Genetic differentiation 1. An individual’s sex is genetically determined by the presence of a Y chromosome 2. Genetic differentiation takes place at fertilization when a sperm delivers either an X (female) or Y (male) chromosome to the oocyte 3. Sex determination gene of the Y chromosome causing the undifferentiated gonad develop into the testis is Sry gene 4. Sry gene of the Y chromosome responsible for the expression of substance called testis determining factor (TDF) secreted by the sex cords. 6. TDF controls the pathway towards either male or female development.
    [Show full text]
  • Reproduction Block Embryology Team
    Reproduction Block Embryology Team Lecture 1: Development of the Male Reproductive Organs Abdulrahman Ahmed Alkadhaib Lama AlShwairikh Nawaf Modahi Norah AlRefayi Khalid Al-Own Sarah AlKhelb Abdulrahman Al-khelaif Done By: Sarah AlKhelb , Nawaf Modahi & Abdulrahman Al-khelaif Revised By: Lama AlShwairikh & Abdulrahman Ahmed Alkadhaib Objectives: At the end of the lecture, students should be able to: List the causes of differentiation of genitalia into the male type. Describe the origin of each part of the male internal & external genitalia. List the causes & describe the events of descent of testis. List the common anomalies of male genital system & describe the causes of each of them. Red = important Green= team notes P.S. 16 pages may seem too many, but the actual work is 10 pages. So, don’t worry about it, and hopefully you’ll find the lecture easy to understand. Best of luck! MALE GENITAL SYSTEM Gonad: Testis. Genital Ducts: Epididymis. Vas deferens. Urethra. Genital Glands: Seminale vesicle (Seminal gland) Prostate. Bulbourethral Glands. DEVELOPMENT OF GONADS During 5th week: Gonadal development occurs. Until 7th week: gonads are similar in both sexes. Gonads are derived from 3 sources: 1. Mesothelium (mesodermal) epithelium lining the coelomic cavity) 2. Underlying mesenchyme 3. Primordial germ cells INDIFFERENT GONADS Gonadal ridge: a bulge on the medial side of mesonephros produced by: 1. Proliferation of mesothelium (cortex) 2. Proliferation of mesenchyme (medulla) Gonadal (primary sex) cords: The proliferating mesothelial cells (of the gonadal ridge) fuse and penetrate the underlying mesenchyme to form gonadal cords. Primordial germ cells: endodermal cells of the yolk sac migrate along dorsal mesentery of hindgut to gonadal ridges & become incorporated into gonadal cords.
    [Show full text]
  • Development of the Genital System Development of the Gonads
    Development of the Genital System Development of the gonads Dr Ahmed Salman The gonads develop form three sources (the first two are mesodermal, the third one is endodermal ) . 1.Proliferating coelomic epithelium on the medial side of the mesonephros. 2. Adjacent mesenchyme dorsal to the proliferating coelomic epithelium. 3. Primordial germ cells (endodermal), which develop in the wall of the yolk sac and migrate along the dorsal mesentery to reach the developing gonad. DR AHMED SALMAN The indifferent stage of the developing gonads - The coelomic epithelium (on either side of the aorta) proliferates and becomes multi layered and forms a longitudinal projection into the coelomic cavity called the genital ridge. - The genital ridge forms a number of epithelial cords called the primary sex cords that invade the underlying mesenchyme, which separate the cords from each other. - Up to the 6th or 7th week, the developing gonad cannot be differentiated into testis or ovary. DR AHMED SALMAN DR AHMED SALMAN Development of the testis and its descent Under the effect of the testis determining factor (T.D.F) present on the short arm of Y - chromosome, the undifferentiated gonad is switched to form a testis. 1. The coelomic epithelium. - The primary sex cords elongate to form testis cords (future seminiferous tubules) which undergo three important events : • Ventrally, they lose contact with the surface epithelium by the developing tunica albuginae. • Dorsally, they communicate with each other to form rete testis. • Internally, they are invaded by the primitive germ cells. DR AHMED SALMAN The testis cords become lined by two types of cells: A.
    [Show full text]
  • Development of Gonads and Sex Differentiation
    Development of gonads and sex differentiation Development of gonads and sex differentiation Chromosomal and genetic sex is established at fertilization and depends upon whether an X-bearing sperm or a Y-bearing sperm fertilizes the X-bearing ovum. The type of gonads that develop, gonadal sex, is determined by the sex chromosome complex (XX or XY). Sex differentiation is a complex process that involves many genes, including autosomal ones. The key to sexual dimorphism is the Y chromosome. This chromosome has a strong testis-determining effect on the medulla of the indifferent gonad. It contains the testis- determining gene, the SRY (sex-determining region on Y) gene on its short arm (Yp11). The protein product of this gene is a transcription factor initiating a cascade of downstream genes that determine the fate of rudimentary sexual organs. The SRY protein is the testis-determining factor. When the transcription factor is expressed in the somatic support cells of the indifferent presumptive gonad, male development occurs. This step is called primary sex determination. If the factor is absent or defective, female development takes place. The sexual genotype is responsible for directing gonadal development (testis versus ovary). The type of gonads present then determines the type of sexual differentiation that occurs in the genital ducts and external genitalia. It is the androgen testosterone, produced by the testes, that determines maleness. Although the chromosomal and genetic sex of an embryo is determined at fertilization by the kind of sperm that fertilizes the ovum, male and female morphological characteristics of sex do not begin to develop until the 7th week.
    [Show full text]
  • Embryology /Organogenesis
    Embryology /organogenesis/ Development and teratology of reproductive system Male or female sex is determined by spermatozoon Y in the moment of fertilization SRY gene, on the short arm of the Y chromosome, initiates male sexual differentiation. • The SRY initiates transformation of indifferent gonads into testes, which produce hormones supporting development of male reproductive organs. • Developed testes produce: - testosterone (T) - stimulates Wolffian ducts development (epididymis with ductuli efferentes + ductus epididymidis and deferent ducts) and - anti-Müllerian hormone (AMH) - suppresses Mullerian ducts development (oviduct, uterus, and upper vagina). • Indifferent stage – until week 7 - 10 • Differentiated stage 1) Development of gonads 2) Development of reproductive passages 3) Development of external genitalia Development of gonads mesonephric ridge (laterally) Dorsal wall of body: urogenital ridge genital ridge (medially), consisting of mesenchyme and coelomic epithelium (Wolffian duct) gonad Embryo, week 5 Three sources of gonad development: 1 – mesenchyme of gonadal ridges (plica genitalis) 2 – coelomic epithelium (mesodermal origin) 3 – gonocytes (primordial cells) gonocytes Primordial germ cells – gonocytes – in endoderm of dorsal wall of yolk sac. Gonocytes migrate along dorsal mesentery of hindgut into the gonadal ridges and induce (!) gonad development. Dorsal mesentery with gonocytes Embryo, weeks 4-6 Indifferent gonad development • Gonocytes induce coelomic epithelium to proliferate - primary proliferation gonocytes, cells of coelomic epithelium in mesenchyme form together: primary sex cords coelomic epith. proliferates and forms cords in mesenchyme of indifferent gonad,gonocytes invade cords. Primary proliferation (in male and female) TESTIS Secondary proliferation (only in female) seminiferous tubules INDIFFERENT tunica GONAD albuginea primary sex cords = medullary cords OVARY ovarian follicles secondary sex cords ONLY = cortical cords in ovary TESTIS: Primary sex cords tubuli semuniferi contorti Gonocytes spermatogonia Coelomic ep.
    [Show full text]