DOCSLIB.ORG

Ovarian Physiology: Follicle Development, Oocyte and Hormone Relationships

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Ovarian Physiology: Follicle Development, Oocyte and Hormone Relationships Anim. Reprod., v.6, n.1, p.16-19, Jan./Mar. 2009 Ovarian physiology: follicle development, oocyte and hormone relationships J.K. Findlay1,4, J.B. Kerr2, K. Britt1, S.H. Liew1,3, E.R. Simpson1, D. Rosairo1,3, A. Drummond1 1Prince Henry’s Institute of Medical Research, Clayton, and the Departments of 2Anatomy & Cell Biology, and 3Obstetrics & Gynaecology, Monash University, Clayton, Victoria, 3168, Australia. Abstract The primordial follicle pool The ovarian follicle is the fundamental unit of Follicles form in the ovary when the ovary. It contains the oocyte that may eventually developmentally arrested germ cells or oocytes in nests ovulate, undergo fertilization and form an embryo. It individually acquire somatic follicular cells and also provides the steroid and protein hormones required organize into discrete ‘resting’ follicles. This event for maintenance of the ovarian cycle, the secondary sex occurs in late pregnancy or early in the postnatal period characteristics and preparation of the uterus for in most mammals. The oocytes in the primordial implantation. Follicle formation and folliculogenesis follicles formed in this way remain in the diplotene have been well documented for many mammalian stage of the first meiotic prophase until they enter the species. However, the control of follicular reserves and growth phase, up to 40-50 years later in women. It is a entry of follicles into the growth path towards atresia or widely held view that the mammalian neonatal ovary ovulation are not well understood. We have investigated contains a finite stockpile of non-growing primordial several aspects of follicle formation and folliculogenesis follicles (Zuckerman, 1951). Commencing at or soon by (a) using unbiased assumption-free stereological after birth, a small number of these primordial follicles methods to accurately count follicles, particularly enter the growth path during which they either primordial follicles in the follicular reserve, (b) testing degenerate (mainly by atresia) or complete maturation the effects of members of the transforming growth and ovulate (<1%). As a result the supply of follicles is factor-β family on folliculogenesis and follicle function, said to decline with age until the pool is exhausted at and (c) examining the role of estrogen in advanced age. The notion of a fixed, non-renewable folliculogenesis using the aromatase knock-out mouse reserve of primordial follicles in the mammalian ovary model. These studies are summarized and reviewed. has been questioned recently, particularly with the Keywords: estradiol, folliculogenesis, mice, TGF-β. proposal that intra and extraovarian germline stem cells could replenish oocytes and form new primordial Introduction follicles (Johnson et al., 2004, 2005). If this is correct, we hypothesized that total primordial follicle numbers The ovarian follicle is the fundamental unit of should remain relatively constant, at least for a the ovary. It contains the oocyte that may eventually significant part of adult reproductive life. ovulate, undergo fertilization and form an embryo. It We quantified all healthy follicles in C57BL/6 also provides the steroid and protein hormones required mouse ovaries from postnatal day 1 to 200 using for maintenance of the ovarian cycle, the secondary sex unbiased stereological methods, immunolabelling of characteristics and preparation of the uterus for oocyte meiosis (germ cell nuclear antigen, GCNA) and implantation, and after ovulation, the corpus luteum ovarian cell proliferation (proliferating cell nuclear provides the hormones essential for establishment and antigen, (PCNA) and electron microscopy (Kerr et al., maintenance of pregnancy. Follicle formation and 2006). Day 1 ovaries contained 7924 ± 1564 (S.E.M.) folliculogenesis have been well documented for many oocytes or primordial follicles, declining on day 7 to mammalian species. However, the control of follicular 1987 ± 203, with 200–800 oocytes ejected from reserves (Tilly and Rueda, 2008) and entry of follicles individual ovaries into the ovarian bursa on that day and into the growth path towards atresia or ovulation day 12. Discarded oocytes and those subjacent to the (Findlay et al., 2002) are not well understood. We have surface epithelium were GCNA-positive indicating their investigated several aspects of follicle formation and incomplete meiotic maturation. From day 7 to 100, folliculogenesis by (a) using unbiased assumption-free mean numbers of primordial follicles per ovary were not stereological methods to accurately count follicles, significantly different by ANOVA, but declined by 200 particularly primordial follicles (Kerr et al., 2006), (b) days to about 10% of those levels. Primordial follicle testing the effects of members of the transforming oocytes were PCNA-negative (Kerr et al., 2006). growth factor-β superfamily on folliculogenesis and It could be argued that our data support the follicle function (Rosairo et al., 2008), and (c) hypothesis of postnatal follicle renewal in postnatal and examining the role of estrogen in folliculogenesis using adult ovaries of C57BL/6 mice, at least between days 7 the aromatase knock-out mouse model (Britt et al., and 100. However, several possibilities remain. We and 2000, 2004a, b; Liew et al., 2008). others have found no evidence for ovarian germline _________________________________________ 4Corresponding author: [email protected] Findlay et al. Ovarian physiology. stem cells in the ovary (Bristol-Gould et al., 2006; proposal that regeneration does occur has generated a Eggan et al., 2006; Kerr et al., 2006). Secondly, the renewed interest in regulation of the size of the counting method, despite being the ‘gold standard’, may primordial pool which varies enormously between not have been accurate enough (i.e., there were strains and within strains over time for reasons that insufficient numbers of ovaries counted to reduce the remain unclear. The role of p63 in oocyte quality and error), and the method of statistical analysis may not quantity deserves further investigation. have been robust enough to detect a small but significant decline in primordial follicle numbers during The role of TGF-β superfamily members in this period, as argued by Faddy and Gosden (2007). folliculogenesis However, we have confirmed the relatively stable number of primordial follicles during this period in Local as well as peripheral hormones or growth adult C57Bl6 mice in a recent study, and analysis of this factors are known to influence folliculogenesis, and our earlier data (Kerr et al., 2006) using regression although the identity and action of many of the local analysis did not reveal a significant decline in numbers factors are not known (Findlay et al., 2002). They of primordial follicles (Kerr et al., unpublished data). include members of the TGF-β superfamily which This leads to the third possibility that there may be very includes TGF-βs, inhibins, activins, bone low, and so far undetectable, rates of follicle exit from morphogenetic proteins (BMPs) and growth the pool up to day 100, and thereafter the rate increases differentiation factors (GDFs) (Knight and Glister, for reasons that are not clear. 2006). Although TGF-β ligands and receptors have been Further research is needed to examine the reported in the ovaries of a range of species (Knight and factors regulating the size of the primordial pool during Glister, 2006; Rosairo et al 2008), the direct effects of reproductive age. The Tilly laboratory claimed that TGF-β ligands on follicular development have not primordial follicle numbers in ovaries of adult C57Bl6 received much attention. The effects of null mutations mice treated with chemical toxins that destroy the in the TGF-β ligand genes on fertility have been oocytes of primordial follicles, recovered primordial difficult to address because the animals either die during follicle numbers to pretreatment levels within 24-36 hr gestation or at weaning (TGF-β1) or exhibit perinatal (Johnson et al., 2005). They concluded that this is lethality (TGF-β2 & 3; Dunker and Krieglstein, 2000). evidence for follicle renewal. We have repeated these Ingman et al. (2006) reported that the TGF-β1 null studies using doxorubicin or trichostatin A and a more mutants bred on a Scid background to reduce the rigorous method of counting follicles (Kerr et al., 2006), inflammatory response, had severely impaired fertility and were unable to demonstrate either by due to irregular ovulation, and a reduction in oocyte immunohistochemical staining or stereological analysis number and developmental competence. Liu et al. that regeneration of primordial follicles occurred after (1999) recorded age-specific effects of TGF-β1 on drug treatment (Kerr et al., unpublished observations), follicles in vitro with only the diameters of preantral arguing against oocyte renewal. A recent study using follicles from adult mice increasing in size. We ovarian transplants in mice, with or without radiation to investigated the potential for TGF-β1 to influence destroy primordial follicles, found no evidence to ovarian follicular growth and differentiation using support the hypothesis that progenitor cells from extra- postnatal and immature ovarian models (Rosairo et al., ovarian sources can repopulate the adult ovary (Begum 2008). TGF-β1 ligand and receptor mRNAs were et al., 2008). present in the rat ovary 4-12 days after birth and at day We also need to understand the reasons for the 25. In order to assess the impact of TGF-β1 on follicle rapid
Load more

Recommended publications
  • FEMALE REPRODUCTIVE SYSTEM Female ReproducVe System
    Human Anatomy Unit 3 FEMALE REPRODUCTIVE SYSTEM Female Reproducve System • Gonads = ovaries – almond shaped – flank the uterus on either side – aached to the uterus and body wall by ligaments • Gametes = oocytes – released from the ovary during ovulaon – Develop within ovarian follicles Ligaments • Broad ligament – Aaches to walls and floor of pelvic cavity – Connuous with parietal peritoneum • Round ligament – Perpendicular to broad ligament • Ovarian ligament – Lateral surface of uterus ‐ ‐> medial surface of ovary • Suspensory ligament – Lateral surface of ovary ‐ ‐> pelvic wall Ovarian Follicles • Layers of epithelial cells surrounding ova • Primordial follicle – most immature of follicles • Primary follicle – single layer of follicular (granulosa) cells • Secondary – more than one layer and growing cavies • Graafian – Fluid filled antrum – ovum supported by many layers of follicular cells – Ovum surrounded by corona radiata Ovarian Follicles Corpus Luteum • Ovulaon releases the oocyte with the corona radiata • Leaves behind the rest of the Graafian follicle • Follicle becomes corpus luteum • Connues to secrete hormones to support possible pregnancy unl placenta becomes secretory or no implantaon • Becomes corpus albicans when no longer funconal Corpus Luteum and Corpus Albicans Uterine (Fallopian) Tubes • Ciliated tubes – Passage of the ovum to the uterus and – Passage of sperm toward the ovum • Fimbriae – finger like projecons that cover the ovary and sway, drawing the ovum inside aer ovulaon The Uterus • Muscular, hollow organ – supports
    [Show full text]
  • Evolution of Oviductal Gestation in Amphibians MARVALEE H
    THE JOURNAL OF EXPERIMENTAL ZOOLOGY 266394-413 (1993) Evolution of Oviductal Gestation in Amphibians MARVALEE H. WAKE Department of Integrative Biology and Museum of Vertebrate Zoology, University of California,Berkeley, California 94720 ABSTRACT Oviductal retention of developing embryos, with provision for maternal nutrition after yolk is exhausted (viviparity) and maintenance through metamorphosis, has evolved indepen- dently in each of the three living orders of amphibians, the Anura (frogs and toads), the Urodela (salamanders and newts), and the Gymnophiona (caecilians). In anurans and urodeles obligate vivi- parity is very rare (less than 1%of species); a few additional species retain the developing young, but nutrition is yolk-dependent (ovoviviparity) and, at least in salamanders, the young may be born be- fore metamorphosis is complete. However, in caecilians probably the majority of the approximately 170 species are viviparous, and none are ovoviviparous. All of the amphibians that retain their young oviductally practice internal fertilization; the mechanism is cloaca1 apposition in frogs, spermato- phore reception in salamanders, and intromission in caecilians. Internal fertilization is a necessary but not sufficient exaptation (sensu Gould and Vrba: Paleobiology 8:4-15, ’82) for viviparity. The sala- manders and all but one of the frogs that are oviductal developers live at high altitudes and are subject to rigorous climatic variables; hence, it has been suggested that cold might be a “selection pressure” for the evolution of egg retention. However, one frog and all the live-bearing caecilians are tropical low to middle elevation inhabitants, so factors other than cold are implicated in the evolu- tion of live-bearing.
    [Show full text]
  • Luteal Phase Deficiency: What We Now Know
    ■ OBGMANAGEMENT BY LAWRENCE ENGMAN, MD, and ANTHONY A. LUCIANO, MD Luteal phase deficiency: What we now know Disagreement about the cause, true incidence, and diagnostic criteria of this condition makes evaluation and management difficult. Here, 2 physicians dissect the data and offer an algorithm of assessment and treatment. espite scanty and controversial sup- difficult to definitively diagnose the deficien- porting evidence, evaluation of cy or determine its incidence. Further, while Dpatients with infertility or recurrent reasonable consensus exists that endometrial pregnancy loss for possible luteal phase defi- biopsy is the most reliable diagnostic tool, ciency (LPD) is firmly established in clinical concerns remain about its timing, repetition, practice. In this article, we examine the data and interpretation. and offer our perspective on the role of LPD in assessing and managing couples with A defect of corpus luteum reproductive disorders (FIGURE 1). progesterone output? PD is defined as endometrial histology Many areas of controversy Linconsistent with the chronological date of lthough observational and retrospective the menstrual cycle, based on the woman’s Astudies have reported a higher incidence of LPD in women with infertility and recurrent KEY POINTS 1-4 pregnancy losses than in fertile controls, no ■ Luteal phase deficiency (LPD), defined as prospective study has confirmed these find- endometrial histology inconsistent with the ings. Furthermore, studies have failed to con- chronological date of the menstrual cycle, may be firm the superiority of any particular therapy. caused by deficient progesterone secretion from the corpus luteum or failure of the endometrium Once considered an important cause of to respond appropriately to ovarian steroids.
    [Show full text]
  • Creating an Artificial 3-Dimensional Ovarian Follicle Culture System
    micromachines Article Creating an Artificial 3-Dimensional Ovarian Follicle Culture System Using a Microfluidic System Mae W. Healy 1,2, Shelley N. Dolitsky 1, Maria Villancio-Wolter 3, Meera Raghavan 3, Alexandra R. Tillman 3 , Nicole Y. Morgan 3, Alan H. DeCherney 1, Solji Park 1,*,† and Erin F. Wolff 1,4,† 1 Program in Reproductive and Adult Endocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA; [email protected] (M.W.H.); [email protected] (S.N.D.); [email protected] (A.H.D.); [email protected] (E.F.W.) 2 Department of Obstetrics and Gynecology, Walter Reed National Military Medical Center, Bethesda, MD 20889, USA 3 Trans-NIH Shared Resource on Biomedical Engineering and Physical Science, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA; [email protected] (M.V.-W.); [email protected] (M.R.); [email protected] (A.R.T.); [email protected] (N.Y.M.) 4 Pelex, Inc., McLean, VA 22101, USA * Correspondence: [email protected] † Solji Park and Erin F. Wolff are co-senior authors. Abstract: We hypothesized that the creation of a 3-dimensional ovarian follicle, with embedded gran- ulosa and theca cells, would better mimic the environment necessary to support early oocytes, both structurally and hormonally. Using a microfluidic system with controlled flow rates, 3-dimensional Citation: Healy, M.W.; Dolitsky, S.N.; two-layer (core and shell) capsules were created. The core consists of murine granulosa cells in Villancio-Wolter, M.; Raghavan, M.; 0.8 mg/mL collagen + 0.05% alginate, while the shell is composed of murine theca cells suspended Tillman, A.R.; Morgan, N.Y.; in 2% alginate.
    [Show full text]
  • Oogenesis [PDF]
    Oogenesis Dr Navneet Kumar Professor (Anatomy) K.G.M.U Dr NavneetKumar Professor Anatomy KGMU Lko Oogenesis • Development of ovum (oogenesis) • Maturation of follicle • Fate of ovum and follicle Dr NavneetKumar Professor Anatomy KGMU Lko Dr NavneetKumar Professor Anatomy KGMU Lko Oogenesis • Site – ovary • Duration – 7th week of embryo –primordial germ cells • -3rd month of fetus –oogonium • - two million primary oocyte • -7th month of fetus primary oocyte +primary follicle • - at birth primary oocyte with prophase of • 1st meiotic division • - 40 thousand primary oocyte in adult ovary • - 500 primary oocyte attain maturity • - oogenesis completed after fertilization Dr Navneet Kumar Dr NavneetKumar Professor Professor (Anatomy) Anatomy KGMU Lko K.G.M.U Development of ovum Oogonium(44XX) -In fetal ovary Primary oocyte (44XX) arrest till puberty in prophase of 1st phase meiotic division Secondary oocyte(22X)+Polar body(22X) 1st phase meiotic division completed at ovulation &enter in 2nd phase Ovum(22X)+polarbody(22X) After fertilization Dr NavneetKumar Professor Anatomy KGMU Lko Dr NavneetKumar Professor Anatomy KGMU Lko Dr Navneet Kumar Dr ProfessorNavneetKumar (Anatomy) Professor K.G.M.UAnatomy KGMU Lko Dr NavneetKumar Professor Anatomy KGMU Lko Maturation of follicle Dr NavneetKumar Professor Anatomy KGMU Lko Maturation of follicle Primordial follicle -Follicular cells Primary follicle -Zona pallucida -Granulosa cells Secondary follicle Antrum developed Ovarian /Graafian follicle - Theca interna &externa -Membrana granulosa -Antrial
    [Show full text]
  • Infertility Investigations for Women
    Infertility investigations for women Brooke Building Gynaecology Department 0161 206 5224 © G21031001W. Design Services, Salford Royal NHS Foundation Trust, All Rights Reserved 2021. Document for issue as handout. Unique Identifier: SURG08(21). Review date: May 2023. This booklet is aimed for women undergoing fertility LH (Luteinising Hormone) Progesterone investigations. Its’ aim is to Oligomenorrhoea - When the provide you with some useful periods are occurring three In women, luteinising hormone Progesterone is a female information regarding your or four times a year (LH) is linked to ovarian hormone produced by the hormone production and egg ovaries after ovulation. It investigations. Irregular cycle - Periods that maturation. LH is used to causes the endometrial lining vary in length We hope you !nd this booklet measure a woman’s ovarian of the uterus to get thicker, helpful. The following blood tests are reserve (egg supply). making it receptive for a used to investigate whether You will be advised to have some It causes the follicles to grow, fertilised egg. ovulation (production of an egg) or all of the following tests: mature and release the eggs Progesterone levels increase is occurring each month and also for fertilisation. It reaches its after ovulation, reaching a to help determine which fertility Hormone blood tests highest level (the LH surge) in maximum level seven days treatments to offer. Follicular bloods tests the middle of the menstrual before the start of the next cycle 48 hours prior to ovulation period. The progesterone test is These routine blood tests are FSH (Follicle Stimulating i.e. days 12-14 of a 28 day cycle.
    [Show full text]
  • Understanding Your Menstrual Cycle If You're Trying to Conceive
    IS MY PERIOD NORMAL? Understanding Your Menstrual Cycle If You’re Trying to Conceive More than 70% 11% 95% of women have or more of of U.S. women start irregular menstrual American women their periods by cycles as menopause suffer from age 16. approaches. endometriosis.1 10% 12% of U.S. women are of women have affected by PCOS trouble getting or (polycystic ovary staying pregnant.3 syndrome).2 Fortunately, your menstrual cycle can tell you a lot about your fertility if you know what to look for. TYPES OF MENSTRUAL CYCLES Only 15% of About Normal = women have 30% of women are fertile only during 21 to 35 days the “perfect” the “normal” fertility 28-day cycle. window—between days 10 and 17 of the menstrual cycle. Day 1 Period starts (aka menses) 27 28 1 2 26 3 25 4 24 5 Day 15-28 23 6 Day 2-14 Luteal phase; Follicular phase; progesterone** 22 WHAT’S NORMAL? 7 FSH released, (follicle- uterine lining 21 8 stimulating matures Give or take a few days, hormone) and a normal cycle looks like this: estrogen released, 20 9 ovulation* begins 19 10 18 11 17 12 16 15 14 13 *ovulation: the process of an ovum (egg) being released from the ovary; occurs 10-14 days before menses. **progesterone: a steroid hormone that tells the uterus to prepare for pregnancy At least 30% of women have an “irregular” cycle either short, long or inconsistent. Short = Long = < 21 days > 35 days May be a sign of: May be a sign of: Hormonal imbalance Hormonal imbalance Ovaries with fewer eggs Lack of ovulation Approach of menopause Other fertility issues Reduced fertility4 Increased risk of miscarriage SIGNS TO WATCH FOR Your menstrual cycle provides valuable clues about your body’s reproductive health.
    [Show full text]
  • A Fixed Formula to Define the Fertile Window of the Menstrual Cycle As the Basis of a Simple Method of Natural Family Planning
    ORIGINAL RESEARCH ARTICLE A Fixed Formula to Define the Fertile Window of the Menstrual Cycle as the Basis of a Simple Method of Natural Family Planning Marcos Are´valo,* Irit Sinai,* and Victoria Jennings* A significant number of women worldwide use periodic basis of the proposed Standard Days method, a simple abstinence as their method of family planning. Many of method of natural family planning (NFP). Survey data them use some type of calendar-based approach to deter- from a number of countries around the world show mine when they should abstain from unprotected inter- that a substantial number of women worldwide use course to avoid pregnancy; yet they often lack correct periodic abstinence as their method of family plan- knowledge of when during their menstrual cycle they are ning.1 Many of these women use calendar-based ap- most likely to become pregnant. A simple method of proaches to determine when they should abstain from natural family planning (NFP) based on a fixed formula to unprotected intercourse to avoid pregnancy. How- define the fertile window could be useful to these women. ever, research also indicates that a significant per- This article reports the results of an analysis of the appli- centage of women who claim to use periodic absti- cation of a fixed formula to define the fertile window. A nence lack correct knowledge of when during their large existing data set from a World Health Organization menstrual cycle they are most likely to become study of the Ovulation Method was used to estimate the pregnant.a Most of these women simply abstain from theoretical probability of pregnancy using this formula.
    [Show full text]
  • Diagnostic Evaluation of the Infertile Female: a Committee Opinion
    Diagnostic evaluation of the infertile female: a committee opinion Practice Committee of the American Society for Reproductive Medicine American Society for Reproductive Medicine, Birmingham, Alabama Diagnostic evaluation for infertility in women should be conducted in a systematic, expeditious, and cost-effective manner to identify all relevant factors with initial emphasis on the least invasive methods for detection of the most common causes of infertility. The purpose of this committee opinion is to provide a critical review of the current methods and procedures for the evaluation of the infertile female, and it replaces the document of the same name, last published in 2012 (Fertil Steril 2012;98:302–7). (Fertil SterilÒ 2015;103:e44–50. Ó2015 by American Society for Reproductive Medicine.) Key Words: Infertility, oocyte, ovarian reserve, unexplained, conception Use your smartphone to scan this QR code Earn online CME credit related to this document at www.asrm.org/elearn and connect to the discussion forum for Discuss: You can discuss this article with its authors and with other ASRM members at http:// this article now.* fertstertforum.com/asrmpraccom-diagnostic-evaluation-infertile-female/ * Download a free QR code scanner by searching for “QR scanner” in your smartphone’s app store or app marketplace. diagnostic evaluation for infer- of the male partner are described in a Pregnancy history (gravidity, parity, tility is indicated for women separate document (5). Women who pregnancy outcome, and associated A who fail to achieve a successful are planning to attempt pregnancy via complications) pregnancy after 12 months or more of insemination with sperm from a known Previous methods of contraception regular unprotected intercourse (1).
    [Show full text]
  • Nomina Histologica Veterinaria, First Edition
    NOMINA HISTOLOGICA VETERINARIA Submitted by the International Committee on Veterinary Histological Nomenclature (ICVHN) to the World Association of Veterinary Anatomists Published on the website of the World Association of Veterinary Anatomists www.wava-amav.org 2017 CONTENTS Introduction i Principles of term construction in N.H.V. iii Cytologia – Cytology 1 Textus epithelialis – Epithelial tissue 10 Textus connectivus – Connective tissue 13 Sanguis et Lympha – Blood and Lymph 17 Textus muscularis – Muscle tissue 19 Textus nervosus – Nerve tissue 20 Splanchnologia – Viscera 23 Systema digestorium – Digestive system 24 Systema respiratorium – Respiratory system 32 Systema urinarium – Urinary system 35 Organa genitalia masculina – Male genital system 38 Organa genitalia feminina – Female genital system 42 Systema endocrinum – Endocrine system 45 Systema cardiovasculare et lymphaticum [Angiologia] – Cardiovascular and lymphatic system 47 Systema nervosum – Nervous system 52 Receptores sensorii et Organa sensuum – Sensory receptors and Sense organs 58 Integumentum – Integument 64 INTRODUCTION The preparations leading to the publication of the present first edition of the Nomina Histologica Veterinaria has a long history spanning more than 50 years. Under the auspices of the World Association of Veterinary Anatomists (W.A.V.A.), the International Committee on Veterinary Anatomical Nomenclature (I.C.V.A.N.) appointed in Giessen, 1965, a Subcommittee on Histology and Embryology which started a working relation with the Subcommittee on Histology of the former International Anatomical Nomenclature Committee. In Mexico City, 1971, this Subcommittee presented a document entitled Nomina Histologica Veterinaria: A Working Draft as a basis for the continued work of the newly-appointed Subcommittee on Histological Nomenclature. This resulted in the editing of the Nomina Histologica Veterinaria: A Working Draft II (Toulouse, 1974), followed by preparations for publication of a Nomina Histologica Veterinaria.
    [Show full text]
  • The Reproductive System
    PowerPoint® Lecture Slides prepared by Meg Flemming Austin Community College C H A P T E R 19 The Reproductive System © 2013 Pearson Education, Inc. Chapter 19 Learning Outcomes • 19-1 • List the basic components of the human reproductive system, and summarize the functions of each. • 19-2 • Describe the components of the male reproductive system; list the roles of the reproductive tract and accessory glands in producing spermatozoa; describe the composition of semen; and summarize the hormonal mechanisms that regulate male reproductive function. • 19-3 • Describe the components of the female reproductive system; explain the process of oogenesis in the ovary; discuss the ovarian and uterine cycles; and summarize the events of the female reproductive cycle. © 2013 Pearson Education, Inc. Chapter 19 Learning Outcomes • 19-4 • Discuss the physiology of sexual intercourse in males and females. • 19-5 • Describe the age-related changes that occur in the reproductive system. • 19-6 • Give examples of interactions between the reproductive system and each of the other organ systems. © 2013 Pearson Education, Inc. Basic Reproductive Structures (19-1) • Gonads • Testes in males • Ovaries in females • Ducts • Accessory glands • External genitalia © 2013 Pearson Education, Inc. Gametes (19-1) • Reproductive cells • Spermatozoa (or sperm) in males • Combine with secretions of accessory glands to form semen • Oocyte in females • An immature gamete • When fertilized by sperm becomes an ovum © 2013 Pearson Education, Inc. Checkpoint (19-1) 1. Define gamete. 2. List the basic components of the reproductive system. 3. Define gonads. © 2013 Pearson Education, Inc. The Scrotum (19-2) • Location of primary male sex organs, the testes • Hang outside of pelvic cavity • Contains two chambers, the scrotal cavities • Wall • Dartos, a thin smooth muscle layer, wrinkles the scrotal surface • Cremaster muscle, a skeletal muscle, pulls testes closer to body to ensure proper temperature for sperm © 2013 Pearson Education, Inc.
    [Show full text]
  • Reproductive Cycles in Females
    MOJ Women’s Health Review Article Open Access Reproductive cycles in females Abstract Volume 2 Issue 2 - 2016 The reproductive system in females consists of the ovaries, uterine tubes, uterus, Heshmat SW Haroun vagina and external genitalia. Periodic changes occur, nearly every one month, in Faculty of Medicine, Cairo University, Egypt the ovary and uterus of a fertile female. The ovarian cycle consists of three phases: follicular (preovulatory) phase, ovulation, and luteal (postovulatory) phase, whereas Correspondence: Heshmat SW Haroun, Professor of the uterine cycle is divided into menstruation, proliferative (postmenstrual) phase Anatomy and Embryology, Faculty of Medicine, Cairo University, and secretory (premenstrual) phase. The secretory phase of the endometrium shows Egypt, Email [email protected] thick columnar epithelium, corkscrew endometrial glands and long spiral arteries; it is under the influence of progesterone secreted by the corpus luteum in the ovary, and is Received: June 30, 2016 | Published: July 21, 2016 an indicator that ovulation has occurred. Keywords: ovarian cycle, ovulation, menstrual cycle, menstruation, endometrial secretory phase Introduction lining and it contains the uterine glands. The myometrium is formed of many smooth muscle fibres arranged in different directions. The The fertile period of a female extends from the age of puberty perimetrium is the peritoneal covering of the uterus. (11-14years) to the age of menopause (40-45years). A fertile female exhibits two periodic cycles: the ovarian cycle, which occurs in The vagina the cortex of the ovary and the menstrual cycle that happens in the It is the birth and copulatory canal. Its anterior wall measures endometrium of the uterus.
    [Show full text]