Animal Science 434SpermiationTemporal Relationships of SpermatogenesisSpermatogenesisMultiple Generations of Germ CellsPowerPoint PresentationSlide 7StagesSlide 9Slide 10Slide 11CycleSlide 13Slide 14Duration of SpermatogenesisCoordination of Stages Form WavesCompartmentalization of Spermatogenesis and the Blood Testis BarrierSeminiferous Tubule and Interstitial TissueInterstitial TissueSlide 20Slide 21Cycles and StagesCompartmentalizationBlood Testis BarrierCapacity for Sperm ProductionSlide 26Slide 27Slide 28Variation in Sperm ProductionApoptosis of Germ CellsOver Population of SpermatogoniaAnimation of SpermatogenesisAnimal Science 434Animal Science 434Lecture 12: SpermatogenesisLecture 12: SpermatogenesisSpermiationSpermiationTemporal Relationships of SpermatogenesisTemporal Relationships of SpermatogenesisSpermatogenesisSpermatogenesis57 daysStallionMultiple Generations of Germ CellsMultiple Generations of Germ CellsBull SpermatogenesisBull SpermatogenesisStagesStages•Specific cellular associations within a small segment of a seminiferous tubule•stages are not the same length in time•Specific cellular associations within a small segment of a seminiferous tubule•stages are not the same length in timeBull Spermatogenesis - StagesBull Spermatogenesis - StagesStagesStages•Specific cellular associations within a small segment of a seminiferous tubule•stages are not the same length in time•Specific cellular associations within a small segment of a seminiferous tubule•stages are not the same length in timeBull Spermatogenesis - StagesBull Spermatogenesis - StagesCycleCycle•progression through sequence of all stages•progression through sequence of all stagesBull Spermatogenesis - CyclesBull Spermatogenesis - CyclesCycleCycle•progression through sequence of all stages•4.7 cycles to form spermatozoa–some species variation•progression through sequence of all stages•4.7 cycles to form spermatozoa–some species variationDuration of SpermatogenesisDuration of SpermatogenesisBull Ram Boar Stallion Mancycle (days) 13.5 10.4 8.3 12.2 16Spermatogenesis 61 47 39 57 75Bull Ram Boar Stallion Mancycle (days) 13.5 10.4 8.3 12.2 16Spermatogenesis 61 47 39 57 75Coordination of Stages Form WavesCoordination of Stages Form Waves•some portion of seminiferous tubule is always releasing sperm •some portion of seminiferous tubule is always releasing spermCompartmentalization of Spermatogenesisand theBlood Testis BarrierCompartmentalization of Spermatogenesisand theBlood Testis BarrierSeminiferous Tubule andInterstitial TissueSeminiferous Tubule andInterstitial TissueInterstitial TissueInterstitial TissueVascular System Provides•Nutrients•Oxygen•Growth Factors•HormonesVascular System Provides•Nutrients•Oxygen•Growth Factors•HormonesBlood VesselBlood VesselTight JunctionsMyoid CellsLuminalAdluminalBasalCompartmentsCompartmentsCycles and StagesCycles and StagesCompartmentalizationCompartmentalization•Basal–mitosis•spermatogonia (A, I, B)•primary spermatocytes•Adluminal–meiosis•primary spermatocytes•secondary spermatocytes•spermatids–spermiogenesis•Lumen–spermiation•Basal–mitosis•spermatogonia (A, I, B)•primary spermatocytes•Adluminal–meiosis•primary spermatocytes•secondary spermatocytes•spermatids–spermiogenesis•Lumen–spermiationBlood Testis BarrierBlood Testis Barrier•Sertoli cells and associated tight junctions •first appears at puberty•induced by FSH•after puberty can be maintained by FSH and/or testosterone•essential for meiosis•Sertoli cells and associated tight junctions •first appears at puberty•induced by FSH•after puberty can be maintained by FSH and/or testosterone•essential for meiosis!!!!!!!!!!Capacity for Sperm ProductionCapacity for Sperm ProductionSpecies Testis Sperm/gm DSPWeight (gm) (X 106) (X 109)Dairy Bull 650 18 10Beef Bull 500 18 8Ram 550 26 14Boar 750 30 25Stallion 165 18 3Man 40 4 .045 - .2Species Testis Sperm/gm DSPWeight (gm) (X 106) (X 109)Dairy Bull 650 18 10Beef Bull 500 18 8Ram 550 26 14Boar 750 30 25Stallion 165 18 3Man 40 4 .045 - .2Duration of SpermatogenesisDuration of SpermatogenesisBull Ram Boar Stallion Mancycle (days) 13.5 10.4 8.3 12.2 16Spermatogenesis 61 47 39 57 75Bull Ram Boar Stallion Mancycle (days) 13.5 10.4 8.3 12.2 16Spermatogenesis 61 47 39 57 75FSHApApAdAdBBPPSpermatogonialRenewal in thePrimateSpermatogonialRenewal in thePrimateStem CellPoolStem CellPoolCapacity for Sperm ProductionCapacity for Sperm ProductionSpecies Testis Sperm/gm DSPWeight (gm) (X 106) (X 109)Dairy Bull 650 18 10Beef Bull 500 18 8Ram 550 26 14Boar 750 30 25Stallion 165 18 3Man 40 4 .045 - .2Species Testis Sperm/gm DSPWeight (gm) (X 106) (X 109)Dairy Bull 650 18 10Beef Bull 500 18 8Ram 550 26 14Boar 750 30 25Stallion 165 18 3Man 40 4 .045 - .2Variation in Sperm ProductionVariation in Sperm Production•Testis Size•Efficiency of spermatogenesis–mitotic division–degeneration of germ cells•Length of spermatogenesis•Testis Size•Efficiency of spermatogenesis–mitotic division–degeneration of germ cells•Length of spermatogenesisApoptosis of Germ CellsApoptosis of Germ Cells•Season•Disease•Trauma or heat•Hormone levels•Normal part of spermatogenesis•Season•Disease•Trauma or heat•Hormone levels•Normal part of spermatogenesisOver Population of SpermatogoniaOver Population of SpermatogoniaSGSGSGSGSGSG SG SG SGBasement MembraneSertoliSertoliTight JunctionTight JunctionPSPSSGSG SGBasement MembraneSertoliSertoliAP APAP APNormalApoptosis InhibitedSGSGSGSGSGSG SG SG SGBasement MembraneSertoliSertoliSGSGAnimation of SpermatogenesisAnimation of
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