Lecture 16Outline of previous lectureI. GrowthII. Hormonesa. Endogenous peptideb. Endogenous steroidc. Anabolic steroidsOutline of current lectureI. Male reproductive systema. Organsb. Functionsc. StructuresII. Female reproductive systema. Functionsb. AnatomyMale reproduction systemReproductive organsVas deferensRetractor penis muscleCauses extension of penisGlands penisScrotumTestesCaput epididymisheadCauda epididymisTailFunction of the maleProduce and maintain supply of spermTermed-spermatogenesisDetect females in estrusUsing-pheromones, visual cuesInseminate females and fertilize the female gamete60 days for sperm cell to produceStructure of Testesspermatic cord-contains vas deferens, pampiniform plexus, and external cremaster muscle nervesvas deferens-transport sperm during ejaculationseminiferous tubule-sperm producing cells-true germinal epitheliumcorpus epididymis- maturation of spermatozoacauda epididymis-final maturation and storage, only sperm capable of fertilizationrete testis-function in sperm transport from seminiferous tubules- 100 tubulesTunica albuginea-connective tissue which hold testis togetherEfferent ductules-6-12 tubules absorb fluidCaput epididymis-function in maturation of spermatozoa, fluid absorptionStructures within CellsSertoli cells- support spermatogenesisLeydig cells-testosterone synthesisIncreasing maturityspermatogoniumPrimary spermatocyteSecondary spermatocyteSpermatidsFunction of TestesProduce spermSertoli cells are involved with control of developmentTransport sperm out of testesNot transported by sperm motilityTestis capsule-tunica albuginea-causes pressure with some smooth muscle contractionSeminiferous tubules-myoid cells contract to move spermatozoaEfferent ductules and caput-water absorption causing the sperm to be drawn toward the epididymisProduce testosteroneLeydig cells-stimulated by LH (luteinizing hormone) from anterior pituitaryTestosterone functionMaintain libido (male sex drive)Stimulates secondary sex characteristics, muscle development, accessory glandsMaintain function of male reproductive tractPenis and muscles for ejaculationThermoregulation of testisTemperature 3-5 C less than body temperature are required for spermatogenesis to occur1st major factor of scrotumScrotal properties that facilitate thermoregulationLocation of testies-outside away from body-air circulationLow insulation: thin skin low subcutaneous fat or hairSweat gland: richly endowed, evaporative coolingTunica dartos: smooth muscle which lines scrotal wallChange in testis location-vary closeness to body wallChange in scrotal area-vary in thickness2nd major factorBlood supply to testisPampiniform plexus:Countercurrent heat exchange causes a cooling of arterial blood supplySingle artery surrounded by a network of veinsConvoluted testicular artery on surface of testisIn ram temperatures decrease before entering testisScrotum, testis, and spermatic cord are all involved in thermoregulationCyptorchidismLack of testis descent into scrotum and thus thermoregulation is absentBilateral: is sterileNo spermatogenesisTestosterone is producedUnilateral: is fertileReduce sperm producing capacityCommon in oars and stallionTestis descend lateFunction of epididymisStorage of sperm: CAUDAOnly approximately ½ sperm produced make it to this point70 % of sperm in CaudaMajor site of sperm numbers in excurrent (outside testis ducts 2%in vas deferensFour days of testicular sperm produce is storedCan be stored for several weeksStored without loss of functionArrest sperm metabolism-sperm doesn’t burn outAllows for repetitive ejaculations of a short periodSperm are indefinitely viable as prolonged sexual rest results in the first couple of collections showing poor sperm qualityFate of unejaculated spermReabsorbed by excurrent duct systemEpididymis, Vas deferens, and ampullaSome selective removal of abnormal sperm in epididymis (macrophages)Sperm lost in urine 87%87% of daily sperm from epididymis of inactive ram are found in urineMasturbation loss of spermManagement problem in boars and stallionsVolume and sperm concentration are inversely relateBreeding Soundness exam BSEFertilityMotilityMorphologyBody conditionFeetFemale reproductive systemOverall functions for the female reproductive tractControl activity of organs (hormonal)Endocrine functionOvary, uterus, fetus, placenta, pituitaryi.e. estrusstimulation of myometrial contractionstransport spermstimulation of myometrial contractionsproduce oocytefemale gamete (haploid)facilitate fertilizationsperm passage from uterus to oviductprovide environment for embryo and fetusearly oviduct, uterus the remainder of pregnancygive birth to fetusdilation of cervix, strong uterine contractionsRecycle to become pregnant againinvolution of uterus, return to positive energy balanceReproductive anatomyVulva:Passageway for urineReceptor for penis during copulationPassageway for fetusVagina:Female organ of copulation at matingBirth canal at parturitionMucosal surface that changes during estrous cycleCervixThick wall extension of uterusPassageway for sperm following breedingSecrets mucous, seal off uterus during pregnancyPassageway of fetusSpecies specificCow has 4-5 annular ringsSow-corkscrewFunctionsSperm barrier in cow and eweTransport spermReservoir for spermBlock bacterial invasionsBirth canalUterus (womb)Incubator fertilized ovumGives nutrients to ovumAids travel of spermSecretory organHas two horn or branchesComponentsHornsTwo cornuaPig length-4-5 inCow-7-8 inFunctionsTransport spermMuscle contractionsSperm motilityAbsorption and phagocytosisPartially prepares sperm for fertilizationProvides environment for embryoSupports development of fetusAt birth-expels fetusRecovers from pregnancyIf not pregnantUterine endometrium releases prostaglandin to cause the CL to regressInterferon tau: pregnancy recognitionAllows CL to be maintainedOviduct:Open ended tube from are of ovary to uterusPassageway for sperm and ovumSite of fertilizationTakes 3-5 day for ovum to travel down uterusFunctionsTransport sperm to site of fertilizationReduce sperm numbers to prevent polyspermyRemove oocyte from surface of ovaryTransport oocyte to site of fertilizationOvary2 ovariesProduce female gameteLargest single cell in the bodyProduces female sex hormone (Estrogen and progesterone)Ovarian structuresFollicleBlister like structure on ovary that contains ovum and hormone rich fluid (liquour folliculi)Graffian: Mature follicleArtetic: Deteriorated follicleCystic: continuous