Introduction - The University of Alabama at Birmingham | UAB



IntroductionThe reproductive system is designed to perpetuate the speciesThe male produces gametes called sperm cellsThe female produces gametes called ovaThe joining of a sperm cell and an ovum is fertilizationFertilization results in the formation of a zygoteOrganization of the Reproductive SystemThe reproductive system includes:GonadsTestes / OvariesReproductive tractAccessory glandsPerineal structuresExternal genitalia Anatomy of the Male Reproductive SystemPrincipal structures of the male reproductive system are:External genitaliaScrotumPenis Anatomy of the Male Reproductive SystemPrincipal structures of the male reproductive system are (continued):TestisEpididymisDuctus deferensEjaculatory ductSpongy urethra (penile urethra)Seminal glandProstate glandBulbo-urethral glandAnatomy of the Male Reproductive SystemThe TestesTestes hang inside a pouch called the scrotum, which is on the outside of the bodyTesticle size5 cm long3 cm wide2.5 cm thick10–15 gAnatomy of the Male Reproductive SystemDescent of the TestesDuring development, the testes form inside the abdominal cavity near the kidneysTestes descend toward the scrotum by passing through the inguinal canalsThe ductus deferens, blood vessels, lymphatics, and nerves remain bundled to the testes in the spermatic cordsAnatomy of the Male Reproductive SystemDescent of the TestesTesticle development requires a temperature approximately 98.6°FHence the development of the testicles within the abdominal cavitySperm development requires a temperature approximately 96.6°FHence the development of sperm cells outside the abdominal cavityAnatomy of the Male Reproductive SystemThe Spermatic CordsConsist of:Ilionguinal nerveGenitofemoral nerveDeferential arteryDuctus deferensPampiniform plexusTesticular arteryTesticular veinAnatomy of the Male Reproductive SystemThe Scrotum and the Position of the TestesDivided into two chambers (scrotal cavities)Chambers are separated by the perineal rapheCan be seen as thickened tissue that extends from the anus, across the scrotum, and along the anterior surface of the penisTunica vaginalis A serous membrane that covers the outside of each testis and covers the inside lining of each scrotal cavityAnatomy of the Male Reproductive SystemThe Scrotum and the Position of the Testes (continued)Muscles of the scrotumDartos muscleContraction causes the wrinkling of the scrotal surfaceCremaster muscleContraction tenses the scrotal sac and pulls it closer to the bodyThe temperature for sperm development is 2°F cooler than body temperatureTherefore, if the temperature is cold outside, the testes move closer to the abdomen to maintain the proper temperatureAnatomy of the Male Reproductive SystemThe Scrotum and the Position of the Testes (continued)The scrotum is highly vascularized by the: Internal pudendal arteries A branch from the internal iliac arteryExternal pudendal arteriesA branch from the femoral arteryInferior epigastric arteries A branch from the external iliac arteryAnatomy of the Male Reproductive SystemThe Scrotum and the Position of the Testes (continued)The scrotum has nerves from the: Hypogastric plexusIlioinguinal nervesGenitofemoral nervesPudendal nervesAnatomy of the Male Reproductive SystemStructure of the TestesTunica albugineaA tough fibrous lining of the testes Extends deep into the testes and forms septaSepta converge toward the mediastinumMediastinum supports ducts that move material toward the epididymisTunica vaginalisFibrous tissue that surrounds the tunica albuginea and is continuous with the surrounding tissue of the epididymisAnatomy of the Male Reproductive SystemHistology of the TestesThe septa of the testes separate the testes into lobulesEach lobule contains seminiferous tubulesSeminiferous tubules begin to uncoil leading to the straight tubules in the mediastinum areaThe straight tubules interconnect with each other forming the rete testisRete testis connects to the efferent ductulesEfferent ductules lead to the epididymis Anatomy of the Male Reproductive SystemHistology of the Testes (continued) There is a space between the coils of the seminiferous tubulesThe cells within this space are the interstitial cellsInterstitial cells produce and release testosteroneAnatomy of the Male Reproductive SystemHistology of the Testes (continued) TestosteroneStimulates spermatogenesisPromotes sperm maturationMaintains the accessory organsDevelops secondary sex characteristicsStimulates growth and developmentStimulates sexual behavior and sexual driveAnatomy of the Male Reproductive SystemSpermatogenesis and MeiosisSpermatogenesis Formation of sperm cellsMeiosisSet of events involved in producing the sperm cellsMeiosis begins in the outer layer of the seminiferous tubulesSpermatogoniaStem cells that will become sperm cellsAnatomy of the Male Reproductive SystemSpermatogenesis and Meiosis (continued) At sexual maturation, spermatogonia divideOne of the cells produced by this division remains in the outer layer of the seminiferous tubules as a stem cellThe other cell produced by this division differentiates to become a primary spermatocyteThe primary spermatocyte begins to undergo meiosisAnatomy of the Male Reproductive SystemMeiosis associated with the formation of sperm cells is called spermatogenesisThe primary spermatocyte undergoes division to produce two secondary spermatocytesEach secondary spermatocyte undergoes meiosis to produce four haploid spermatidsEach spermatid matures to become a haploid sperm cellHaploid sperm cells contain 23 chromosomesAnatomy of the Male Reproductive SystemSpermiogenesisSpermatids will mature to form a spermatozoon (sperm cell)This maturation process is called spermiogenesisWhile the spermatids are maturing, they become embedded in nurse cellsUpon maturation, the spermatids (now sperm cells) enter into the lumen of the seminiferous tubulesAnatomy of the Male Reproductive SystemNurse CellsFunction of Nurse CellsMaintenance of the blood–testis barrierSupport of spermatogenesisSupport of spermiogenesisSecretion of inhibinControls the rate of sperm formationSecretion of androgen-binding protein (ABP)Binds testosterone within the seminiferous tubules so testosterone will continue to have an effect on spermiogenesisAnatomy of the Male Reproductive SystemAnatomy of a SpermatozoonEach spermatozoon has three areasHeadContains chromosomesContains acrosomal cap consisting of enzymesEnzyme, hyaluronidase, is necessary for fertilization of the eggMiddle piece (with the neck)Contains mitochondriaTailCalled the flagellumEnables mobility of the sperm cellAnatomy of the Male Reproductive SystemThe Male Reproductive TractEpididymisDuctus deferensUrethraAnatomy of the Male Reproductive SystemThe EpididymisSperm cells move from the seminiferous tubules (via fluid movement) eventually to the epididymis to mature a little longerThe epididymis consists of three partsHeadReceives spermatozoa via the efferent ductsBodyCoiled tubes pass through the bodyTailTubes begin to uncoil to become a single tube called the ductus deferensAnatomy of the Male Reproductive SystemFunctions of the EpididymisMonitors the composition of the fluid in the seminiferous tubulesRecycling center for damaged spermatozoaStores spermatozoa for further maturation (about two weeks)Mature sperm cells are not active until they become capacitatedAnatomy of the Male Reproductive SystemFunctions of the Epididymis (continued)The process of capacitationSperm cells become motile when mixed with secretions from the seminal glandsBecome capable of fertilizing an egg when exposed to the female reproductive tractAnatomy of the Male Reproductive SystemThe Ductus DeferensAlso called the vas deferensBegins at the tail of the epididymisAscends into the abdominal cavity through the inguinal canalCurves around the urinary bladder and the ureterDescends back toward and through the prostate glandBefore entering the prostate gland, the ductus deferens expands (ampulla) and becomes the ejaculatory ductThe ejaculatory duct enters the prostate glandAnatomy of the Male Reproductive SystemThe UrethraDivided to form three regionsProstatic urethraExtends from the urinary bladder through the prostate glandMembranous urethraThe merging of the prostatic urethra and the ejaculatory ductSpongy urethraPasses through the penisSometimes called the penile urethraAnatomy of the Male Reproductive SystemThe Accessory GlandsThere are three glands associated with the male reproductive systemSeminal glands (or seminal vesicles)Prostate glandBulbo-urethral glands (or Cowper’s glands)Anatomy of the Male Reproductive SystemThe Accessory Glands (continued)The seminal glands Produce 60 percent of the semen volumeSeminal fluid consists ofA high concentration of fructoseProstaglandinsClotting factorsContents empty into the ductus deferensAnatomy of the Male Reproductive SystemThe Accessory Glands (continued)The prostate glandContents empty into the prostatic urethraProduces 20–30 percent of the semen volumeWeakly acidicSecretions consist of seminalplasminThis is an antibiotic believed to prevent UTIs in malesAnatomy of the Male Reproductive SystemThe Accessory Glands (continued)The bulbo-urethral glandsPaired glands located at the base of the penisProduces 5 percent of the semen volumeContents empty into the spongy urethraSecretions Consists of thick, sticky, alkaline mucusNeutralizes urinary acids that are remaining in the urethraProvides lubrication for the tip of the penisAnatomy of the Male Reproductive SystemSemenEach ejaculation releases 2 to 5 ml of semenEjaculate material consists of:Spermatozoa20 million to 100 million per mlSeminal fluid60 percent from the seminal vesicles30 percent from the prostate5 percent from the bulbo-urethral glands5 percent from the epididymisEnzymesDissolves vaginal mucus and acts as an antibioticAnatomy of the Male Reproductive SystemThe PenisDivided into three regionsRootAttaches to the rami of the ischiaBodyConsists of erectile tissueGlansThe expanded distal end of the penisSurrounds the external urethral orificeAnatomy of the Male Reproductive SystemThe PenisConsists of three cylindrical columns of erectile tissue and blood vesselsTwo corpora cavernosaOne corpus spongiosumAnatomy of the Male Reproductive SystemThe PenisThe corpora cavernosa Deep artery of the penis is in the center of this tissueEach corpus cavernosum extends posteriorly forming a crus of the penisEach crus is bound to the ramus of the ischiumThe corpus spongiosumConsists of the spongy urethraAnatomy of the Male Reproductive SystemErection of the PenisParasympathetic nerves are activatedSmooth muscles in the arterial walls relaxArterial vessels dilateArterial vessels and vascular channels within the corpora cavernosa become engorged with bloodErection occursAnatomy of the Male Reproductive SystemSemen Release and EjaculationThe sympathetic nerves cause peristaltic action in the: Ductus deferensSeminal glandsProstate glandBulbo-urethral glandsEjaculation occursAnatomy of the Female Reproductive SystemOverview of the Female Reproductive SystemOvariesFimbriaeUterine tubesUterusVaginaAnatomy of the Female Reproductive SystemNumerous structures aid in anchoring the ovaries, uterine tubes, and uterusBroad ligamentMesosalpinxMesovarium Ovarian ligamentSuspensory ligamentRound ligamentUterosacral ligamentAnatomy of the Female Reproductive SystemThe OvariesConsist of: CortexGamete production occurs hereMedullaAnatomy of the Female Reproductive SystemThe Ovarian Cycle and OogenesisOogenesis is the production of female gametesPrevious thoughts:Unlike the males, this process begins before birthCurrent research:This might not be the caseAnatomy of the Female Reproductive SystemThe Ovarian Cycle and Oogenesis (details)At puberty, the follicle-stimulating hormone (FSH) from the pituitary gland initiates the cyclePrimordial follicles develop into primary folliclesDuring this development, several layers of cells form around the folliclesZona pellucidaThis layer consists of granulosa cellsThese cells form interdigitating microvilli to the oocyteThese cells also produce estrogenAnatomy of the Female Reproductive SystemThe Ovarian Cycle and Oogenesis (details)The layer surrounding the zona pellucida:Thecal cellsThese cells also release estrogenEstrogen functionsStimulates bone and muscle growthMaintains female secondary sex characteristicsAffects sex-related behaviors and drivesMaintains function of reproductive glands and organsInitiates repair and growth of uterine liningAnatomy of the Female Reproductive SystemThe Ovarian Cycle and Oogenesis (details)The primary follicles develop to form secondary folliclesSecondary follicles enlarge greatly due to fluid production by the follicular cellsAnatomy of the Female Reproductive SystemThe Ovarian Cycle and Oogenesis (details)The secondary follicles become tertiary folliclesThis is the mature follicle (also called Graafian follicle)This follicle is large enough to cause the ovarian walls to stretchThe tertiary follicle is preparing to ovulate the eggAnatomy of the Female Reproductive SystemThe Ovarian Cycle and Oogenesis (details)Ovulation: gamete releaseThe follicular cells around the oocyte are now called the corona radiataThere is a rise in the concentration of the luteinizing hormone (LH)—this causes a weakening in the follicular wallThe egg is released eventually into the uterine tubeAnatomy of the Female Reproductive SystemThe Ovarian Cycle and Oogenesis (details)After the release of the egg, the empty follicle is called a corpus luteumThe corpus luteum produces progesteroneProgesterone is used to prepare the body for pregnancyIf pregnancy does not occur, the corpus luteum decomposes (about 12 days after ovulation) and becomes the corpus albicansAnatomy of the Female Reproductive SystemAge and OogenesisAt puberty, there are about 200,000 primordial follicles per ovaryForty years later, only about 500 will have been ovulatedThe rest decomposeAnatomy of the Female Reproductive SystemThe Uterine TubesConsist of four regionsInfundibulumAmpullaIsthmusUterine partAnatomy of the Female Reproductive SystemFour Regions of the Uterine TubesInfundibulumHas numerous fimbriaeInner lining of infundibulum contains ciliaAmpullaIsthmusUterine partOpens into the uterusAnatomy of the Female Reproductive SystemHistology of the Uterine TubeConsists ofCiliated and nonciliated columnar cellsLayers of smooth muscle Used for peristaltic actionSuccessful fertilization Occurs 12–24 hours after ovulationOccurs in the distal 2/3 of the uterine tube (ampulla region)Anatomy of the Female Reproductive SystemThe UterusProvides protection for the embryoProvides nutritional support for the embryoProvides a means to remove waste produced by the embryoAnatomy of the Female Reproductive SystemThe UterusOverall sizePear-shaped7.5 cm long5 cm diameter30–40 gAnatomy of the Female Reproductive SystemSuspensory Ligaments of the UterusThese are in addition to the various regions of the broad ligamentUterosacral ligamentsRound ligamentsCardinal ligamentsAnatomy of the Female Reproductive SystemSuspensory Ligaments of the UterusPosition of the suspensory ligamentsUterosacral ligamentsExtend from the lateral edge of the uterus to the anterior face of the sacrumRound ligamentsExtend from the lateral edge of the uterus just inferior to the base of the uterine tubes, pass through the inguinal canal to the connective tissue of the external genitaliaCardinal ligamentsExtend from the base of the uterus and vagina to the lateral walls of the pelvisAnatomy of the Female Reproductive SystemInternal Anatomy of the UterusConsists of:BodyFundusCervixExternal osCervical canalUterine cavityInternal osAnatomy of the Female Reproductive SystemThe Uterine WallThe uterine wall consists of three layersEndometriumMyometriumConsists of longitudinal, circular, and oblique smooth musclesPerimetriumAnatomy of the Female Reproductive SystemBlood Supply to the UterusUterine arteries arise from the internal iliac arteriesOvarian arteries arise from the abdominal aorta inferior to the renal arteriesAnatomy of the Female Reproductive SystemHistology of the UterusThe endometrium is subdividedFunctional layerThis layer is closest to the uterine cavityContains uterine glandsUndergoes cyclic changes due to hormonesBasilar layerThis layer is closest to the myometriumRemains relatively constant Anatomy of the Female Reproductive SystemThe Uterine CycleThe uterine cycle is the menstrual cycleConsists of three phasesProliferative phaseSecretory phaseMensesAnatomy of the Female Reproductive SystemPhases of the Uterine CycleMenarcheThis is the first uterine cycle at pubertyProliferative phaseEndometrial lining thickens preparing the body for the implantation of a fertilized eggSecretory phaseEndometrial glands enlarge and blood vessels elongateAn egg is ready to implant (if an egg is present)Anatomy of the Female Reproductive SystemPhases of the Uterine CycleMensesBegins due to a decrease in progestin and estrogen levels This causes constriction of blood vesselsThis causes a loss of the excess endometrial cellsThis is menstruationMenopauseThe last uterine cycleAnatomy of the Female Reproductive SystemThe VaginaExtends from the cervix of the uterus to the external genitaliaVagina is approximately 7.5–9 cm in lengthCervix projects from the uterus into the vaginal canalThe edges of the cervix form recesses called the fornixThe urethra, vaginal canal, and rectum are in close proximity to each otherAnatomy of the Female Reproductive SystemThe VaginaServes three major functionsPassageway for elimination of menstrual fluidsReceives the penis and holds spermatozoa before they enter the uterusServes as a passageway for the fetus during vaginal birthAnatomy of the Female Reproductive SystemThe VaginaContains a normal population of bacteriaBacteria are provided nutrients found in the cervical mucusThe bacteria create an acid environmentThis reduces the growth of many pathogenic organismsThis also reduces sperm mobilityBuffers found in seminal fluid counteract this acidityAnatomy of the Female Reproductive SystemHistology of the VaginaLined with stratified squamous epitheliumWhen relaxed, this tissue forms rugaeLamina propria is thick and elasticThe muscular layer is continuous with the myometrium of the uterusAnatomy of the Female Reproductive SystemThe External GenitaliaVulvaVestibuleLabia minoraClitorisPrepuceLabia majoraMons pubisHymen (when present)Anatomy of the Female Reproductive SystemThe External Genitalia (details)VulvaThe entire genitalia areaVestibuleThe opening into the vagina surrounded by the labia minoraClitorisContains erectile tissueLabia majora and mons pubisForms the lateral and superior edges of the vestibuleAnatomy of the Female Reproductive SystemThe Mammary GlandsConsist of:Lobes of mammary glandsMilk leaves the lobesLactiferous ductsDucts lead to the nippleNippleAreolaSuspensory ligaments ................
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