Blastulation! Gap Junctions! Inner Cell Mass! Zona Pellucida! Placentation and Maternal Recognition of Pregnancy! Trophectoderm! Na+! [Na+]! Animal Science 434! John J. Parrish! H2O! Tight Junctions! Hatching! Conceptus Growth! Cow! • Day 15, 1-2 mm! Occurs in cow, pig and sheep! Bovine! • Day 18-19, 10-20 cm! » 9 - 11 days! Spherical! Embryonic Equine, Ovine! Area! » 7 - 8 days! Porcine! Tubular! Elongating! » 6 days! Trophoblast! Filamentous! Mare remains spherical!! Development of Porcine Conceptuses Elongated Day 15 Porcine from Day 10 to 12! Conceptus! 5 mm Spherical 10 mm Spherical Inner Cell Mass 15 mm Tubular 150 mm Filamentous Embryo 1! Uterine Location of Elongating Pig Intrauterine Migration! Ruminant Blastocyst! Day 5! Corpus! Luteum! Bovine and Ovine! Pig Intrauterine Migration! Pig Intrauterine Migration! Day 7! Day 12! Embryos become fixed! Transuterine migration is rare in cow and ewe!! Trans-uterine Migration in the Mare! Gastrulation! Begins Day 10! Inner Cell Mass! Trophectoderm! Formation Endoderm! of Germ Fixation can Fixation occur in either on day Layers! horn!! 15 - 16! Blastocoele! Corpus! Cavity! Luteum! 2! Gastrulation! Gastrulation! Endoderm! Endoderm! Yolk Sack! Yolk Sack! Gastrula! Gastrula! Ectoderm! Mesoderm! Ectoderm! Trophectoderm! Extraembryonic! Coelom! Yolk Sack! Endoderm! Endoderm! Trophectoderm (Chorion)! Germ Layers! Placenta Formation! Embryonic! Amniotic Folds! Ectoderm! Mesoderm! Endoderm! Ectoderm! » CNS! » Circulatory! » Digestive ! » Sense organs! » Skeletal! » Liver! » Mammary » Muscle! » Lungs! glands! » Reproductive » Pancreas! Extraembryonic » Sweat glands! tracts! » Thyroid gland! Ceolom! » Skin! » Kidneys! » Other glands! Yolk » Hair! » Urinary ducts! Sack! » hooves! Trophectoderm! Chorion! Mesoderm! Endoderm! 3! Amniotic Fold! Amnionic Cavity! Amniotic Cavity! Amnion! Uterine! Lumen! Allantois! Extraembryonic Yolk Ceolom! Allantois! Sack! Yolk Sack! Chorion! Chorion! Extraembryonic Carnuncle! Ceolom! Amniotic Cavity! Chorion! Placental Membranes! Amnion! Yolk Sack! » In birds to nourish embryo! » In mammal atrophies but source of blood cells and primordial germ cells! Amnion! » Non-vascular, fluid filled! Allantois Cavity! » Fluid produced by fetus! Yolk! » Protective cushion! Sack! » Ruptures at birth (not breaking of water)! Allantochorion! Cotyledon! (Chorioallantois)! Placental Membranes (cont.)! Allantois! » Blood vessels! » Fuses with chorion! • Allantochorion or chorioallantois! Maternal Recognition of Pregnancy! • Brings blood vessels to chorion! Chorion! » Outermost membrane! » Attachment to mother! 4! Luteal Regression! CL Status! CA! !Mechanisms" CL Regression! • Luteolytic! (+)! • No CL support! CL! Uterine PGF2α ! CL Maintenance! PGF ! • Antiluteolytic! 2α » Block PGF effects! (Bovine, Ovine,! Filamentous Embryo! 2α PGF • Luteotrophic! Porcine)! 2α (+)! (Equine)! » Stimulate progesterone production by CL! No Uterine Factor! Maintained! (human)! Recognition of Pregnancy in Bovine Recognition of Pregnancy! and Ovine! Conceptus Secretions! • Interferons! Mechanism! • oIFN-τ! Conceptus Secretions! • Antiluteolytic! • bIFN-τ! • Proteins! • Inhibit oxytocin • Steroids! receptor synthesis! Critical Days! • Inhibit PGF2α synthesis! • Bovine - 16 to 17! • Ovine - 12 to 13! Recognition of Pregnancy in the Porcine! Recognition of Pregnancy in the Porcine! E2! E2! PGF2α! E2! PGF2α! PGF2α! PGF2α! E ! E2! 2 E2! PGF2α! PGF2α! 5! Recognition of Pregnancy in the Porcine! Recognition of Pregnancy in the Mare! Conceptus Secretions! • Estradiol! E2! E2! Critical Days! PGF2α! E2! PGF2α! 11 to 12! PGF2α! E2! E2! E2! PGF2 α PGF2α PGF2α! Mechanism! Conceptus Secretion! Mechanism! • Antiluteolytic! • ?! • antiluteolytic! » Redirect PGF ! 2α Critical Days! » Requires 2 embryos per horn! 10 to 14! Recognition of Pregnancy in the Human! Recognition of Pregnancy! Conceptus Secretes! • HCG! Mechanism! • luteotrophic! INF-τ! HCG! HCG! Conceptus Secretions! Critical Days! Estradiol! • 8 to 12! • Proteins! • Steroids! Dog and Cat! CL does not regress if not pregnant ! » no uterine effect! Psuedopregnancy! » CL last similar length as in pregnancy! Implantation! 6! Time of Implantation! Type of Implantation! Attachment to Uterus! Superficial! Species! Beginning! Completion! » Chorion lies opposed to uterine wall! » Farm animals! !pig !13 !24! Eccentric! !cow !22 !40! » Chorionic sack in a uterine fold! !sheep !15 !28! » Rodent! !mare !24 - 40 !95 - 100! Interstitial! !human !7 - 8 !30! » Embryo digests part of uterine wall! » human! Degree of Tissue Loss at Parturition! Shape or Distribution of Chorionic Villi! Deciduate! Cotelydonary - cow, sheep! » Eccentric, interstitial! Diffuse - pig, horse! » Rodent, human! Zonary - dog, cat! Indeciduate or Nondeciduate! Discoid - human! » Superficial! » Farm animals! Cotelydonary Cotelydonary Placenta! Placenta! Cow! Cow! Convex! Ewe! Placentome! Ewe! Cotelydon (Chorion)! Concave! Caruncle! 70 - 120! 90 - 100! Endometrium! 7! Placental Attachment in Ruminant! Day 23 Migration of Bicnucleate Cells and Formation of Syncytium Binucleate! Chorion Cell! Migrate and" fuse with" uterine" Binucleate Uterine epithelium " Cell Epithelium Syncytium! Capillary Fusion of" Binucleate" Endometrial cells and " Stroma uterine" Stroma epithelium" Multinucleated Cells in (multinucleate) " Uterine Epithelium Binuclear Giant Cells! Placental Lactogens (Protein Hormones) !20% of fetal placenta! Prolactin-like activity: Stimulates Milk Synthesis !Invade endometrium! Not Present in Pig and Mare !Source! »!Placental lactogen! •! May regulate maternal metabolism to facilitate fetal growth" »!Pregnancy specific protein B! •! High levels in the last 1/3 of gestation." •! High levels facilitate higher milk production." •! Dairy cows have higher blood concentrations than beef cows! Pregnancy Specific Protein B! Diffuse Placenta! Horse! !Unique to ruminants! Pig! !Function uncertain! !Has been used to detect pregnancy! »!Cattle, sheep, deer ! •! Can be used to detect pregnancy in cows after day 25! »!Not early pregnancy factor!!!! Microcotyledons! 8! Microcotelydons! Increase placental Endometrial Cups in Mare! surface area! Microcotelydon" !From both trophoblast and endometrium! (Fetal)! Microcotelydon! !5 to 10! Epithelium! !Form between days 35 to 60! Microcotelydon! Endometrium !Produce equine chorionic gonadotropin (Maternal)! (eCG, PMSG)! Endometrial !Sloughed off after day 60! Glands! ! Uterine Arteries! Uterine Veins! Zonary Placenta" Discoid Placenta" (bitch, queen)! (human)! Cell Layers Separating Maternal and Fetal Blood! Histological Classification! Fetal! Maternal! Tissues !epithelial- !syndesmo- !endothelial- !hemo- !hemo-! Capillary! Capillary! !chorial !chorial !chorial !chorial !endothelial! Maternal! endothelium !+ !+ !+ !- !-! conn. tissue !+ !+ !- !- !-! epithelium !+ !- !- !- !-! Fetal !! epithelium !+ !+ !+ !+ !-! Endothelium! Endothelium! conn. tissue !+ !+ !+ !+ !-! endothelium !+ !+ !+ !+ !+! Connective! Connective! Species !pig !*ruminant !dog !human !rat! Tissue! Tissue! !horse ! !cat ! !rabbit! Chorionic! Endometrial! !ruminant! Epithelium! Epithelium! 9! Important!!!!! !In all cases, fetal and maternal blood does not mix.! 10!.