4Epidydimus Fluid reabsorption Quiescence of sperms Increase concentrations of sperm by 100 foldsEstrogen dependentQuiescence of spermsSlow activityMovement depends on musculatureAddition of chemicalsGlycoproteinsCoating of sperm surface
5Maturation of sperm Ability to move on its own Nuclear condensation and loss of cytoplasmMetabolism alterationExternal sourceIncreased mobilityChanges in cell membraneIncreased charge (glycosylation)Changes in protein profileChanges in lipid composition (fluidity)
6Maturation of sperm Androgen dependent Very high concentrations (ABP)Conversion to DHTIncreased bioactivityEntire process will take several months to few days
7Movement of sperms Entering vas deference from epidydimus Muscular contraction rather than fluid movementDense massServe as reservoir of spermsLost in urine if no ejaculation
8Sperm in male reproductive tract SemenSperm plus seminal plasmaSeminal plasmaDerived from accessory sex glandsServes as fluid vesicle for transportUnnecessary for sperm function
9Seminal plasma Derived from accessory sex glands Serves as fluid vesicle for transportServes as bufferBasic in natureNeutralizes acidsProvides nutrientsFluctosesorbitol
12Deposition of semen into the female reproductive tract CoitusPhysiological changesGenitaliaOther parts of bodyPhasesDescribed in humans by Johnson and MastersFour phasesExcitement (sexual arousal)Plateau (intense arousal)Orgasm (involuntary climax)ResolutionAbsolute refractory phase in maleImmediately after orgasm
13Excitement Vasocongestion Vaginal expansion “Tenting effect” on uterus Penile erection (engorgement of corpora cavanosa and corpus spongiosum)Vaginal lubrication (transudation)Enlargement of labia minora and clitorusVaginal expansion“Tenting effect” on uterusUpward movement of uterus and cervixFibrilation of uterus (contraction)Sex flushMyotoniaIncreased muscle tension
14Plateau Increased testis size Secretion of fluid Sex flushes Elevated from the original positionSecretion of fluidCowper’s glandSex flushesEngorgement of vaginal wallOrgasmic platformFormation of seminal pool
16Male orgasm Contraction of accessory sex gland Collection of semen into the urethral bulbContraction of bladder muscleEmission stage of ejaculationExpulsion of semen/ejaculationMuscle contractionReproductive tract contraction
17Resolution Returning of body to nonaroused state Size of genitalsUptake of sperm by the cervixDipping into the seminal pool as the uterus returns to the normal positionOpening of cervical canal
18Site of semen deposition Varies among speciesHumans and cattleNear external portion of cervix (cervical os)Uterus in other speciesFormation of “plug”Enzymatic reactionPrevent backflow of semenBuffersPrevent sperm from other males to fertilize eggs?
19Transport of sperm to the oviduct Sperm must enter female reproductive tract and reside there for some timeMaximum fertilitySpermViable inside of reproductive tract24 to 48 hours in human30 to 48 hours in cowsOocyteA finite life span6 to 24 hours after ovulation in humanSperm must reach the oviduct at appropriate time in order to remain viable and fertile
20Transport of sperm to the oviduct PreovulatryfollicleSemen poolSemenDeposited in the anterior part of the vagina near the cervixThe majority of the spermLost because of retrograde flow of the mucus out of the vaginaKilled because of the unfavorable environment for sperm survival in the vagina.
21Transport of sperm to the oviduct Some of the spermTransported through cervical canal into the uterus within minutes after sperm depositionRapid transportRapid transport of sperm is caused by the contraction of myometrium (muscle layer of the uterus) and not by active movement of spermSperm that enter the oviduct by rapid transportOften non-viable and unlikely to participate in fertilization.
22Transport of sperm to the oviduct Many spermTrapped in the folds and crypts of the cervixFormation of sperm reservoirs within the cervixCriticalMore sperm ultimately reach the oviduct when more sperm are available in the cervical reservoirFolds and crypts of the cervix
23Transport of sperm to the oviduct Slow transport of spermAfter establishment of reservoirEnsures the availability of sperm in the oviduct continuouslyLarge number of spermsFails to reach the oviductMany obstacles such as folding of the uterine endometrium and the narrow diameter of the uterotubal junctionPresumably to prevent polyspermy (more than one sperm fertilizing the oocyte)
24Transport of sperm to the oviduct UterotubalJunctionAmpullary-isthmic JunctionIsthmusAmpullaInfundibulumAggregation of spermsThe isthmusSperm remain in the isthmus until ovulationHyperactivationRapid movement of tail and erratic swimming motionNear ovulationEssential for their upward movement toward the ampulla.
25Transport of sperm to the oviduct UterotubalJunctionAmpullary-isthmic JunctionIsthmusAmpullaInfundibulumCapacitationChanges in cell surface of the spermRequired for proper attachment and penetration of the zona pellucida when the sperm encounters the oocyte
26Capacitated sperms Acrosome reaction when encountering the oocyte Ability to bind and penetrate zona pellucidaSwelling of acrosomeFusion of acrosomal membraneExocytosis of acrosomal contentCa and cAMP dependent
28Acrosome reaction Triggered by the protein in the zona pellucida ZP3 Sperms have receptors for ZPsIncreased Ca uptakeRelease of hexosaminidase B (removal of ZP3)
29Acrosome reaction Must take place near the oocyte Reduced sperm viability
30Fertilization Sperm encountering the oocyte Cumulus cells Migration through the remaining cumulus cells that surround the oocyteSperm binds to the zona pellucidaMediated by the sperm binding sites present on zona pellucidaCumulus cellsFirst polar body
31FertilizationWithin minutes of binding, the sperm begins to penetrate the zona pellucida, and eventually fuses with the oocyteEquatorial and postacrosomal regionCa-dependent reactionImmediately after the sperm fuses with the oocyte, the oocyte extrudes the second polar bodyOocyte becomes a haploid cellZonapellucidaSecond polar body
32FertilizationOnce a sperm fuses with the oocyte, the zona pellucida becomes hardenedRelease of CaSperm binding sites disappear from the zona pellucidaHardening of zona and loss of sperm binding sites are necessary in order to prevent polyspermyHeadof sperm
33Fertilization Membrane of the sperm head Degraded and replaced by a new membraneFormation of a structure called the male pronucleusThe maternal half of chromosomesThe female pronucleus.Male pronucleusFemale pronucleus
34FertilizationMale and female pronuclei move toward the center of the oocyteDegradation of the membrane that surrounds each pronucleusMixing of maternal and paternal chromosomesRestoration of the total number of chromosomesZygote