1 / 52

Lecture 19 Placentation and Maternal Recognition of Pregnancy

Lecture 19 Placentation and Maternal Recognition of Pregnancy. Animal Science 434 John J. Parrish. Gap Junctions. Inner Cell Mass. Zona Pellucida. Trophectoderm. Na +. [Na + ]. H 2 O. Tight Junctions. Blastulation. Hatching. Bovine 9 - 11 days Equine, Ovine 7 - 8 days Porcine

ellis
Download Presentation

Lecture 19 Placentation and Maternal Recognition of Pregnancy

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Lecture 19Placentation and Maternal Recognition of Pregnancy Animal Science 434 John J. Parrish

  2. Gap Junctions Inner Cell Mass Zona Pellucida Trophectoderm Na+ [Na+] H2O Tight Junctions Blastulation

  3. Hatching • Bovine • 9 - 11 days • Equine, Ovine • 7 - 8 days • Porcine • 6 days

  4. Embryonic Area Spherical Tubular Elongating Trophoblast Filamentous Conceptus Growth • Cow • Day 15, 1-2 mm • Day 18-19, 10-20 cm Occurs in cow, pig and sheep Mare remains spherical!

  5. Development of Porcine Conceptuses from Day 10 to 12 5 mm Spherical 10 mm Spherical Inner Cell Mass 15 mm Tubular 150 mm Filamentous

  6. Elongated Day 15 Porcine Conceptus Embryo

  7. Uterine Location of Elongating Ruminant Blastocyst Corpus Luteum Bovine and Ovine

  8. Pig Intrauterine Migration Day 5

  9. Pig Intrauterine Migration Day 7

  10. Day 12 Embryos become fixed Pig Intrauterine Migration Transuterine migration is rare in cow and ewe!

  11. Fixation can occur in either horn! Fixation on day 15 - 16 Transuterine Migration in the Mare Begins Day 10 Corpus Luteum

  12. Gastrulation Trophectoderm Inner Cell Mass Formation of Germ Layers Endoderm Blastocoele Cavity

  13. Endoderm Endoderm Yolk Sack Gastrulation

  14. Gastrula Ectoderm Trophectoderm Endoderm

  15. Gastrula Ectoderm Mesoderm Extraembryonic Coelom Yolk Sack Trophectoderm (Chorion) Endoderm

  16. Ectoderm CNS Sense organs Mammary glands Sweat glands Skin Hair hooves Mesoderm Circulatory Skeletal Muscle Reproductive tracts Kidneys Urinary ducts Germ Layers • Endoderm • Digestive • Liver • Lungs • Pancreas • Thyroid gland • Other glands

  17. Placenta Formation Embryonic Ectoderm Amniotic Folds Extraembryonic Ceolom Yolk Sack Trophectoderm Chorion Mesoderm Endoderm

  18. Amniotic Fold Amniotic Cavity Allantois Extraembryonic Ceolom Yolk Sack Chorion

  19. Amnionic Cavity Amnion Uterine Lumen Allantois Yolk Sack Chorion Extraembryonic Ceolom Carnuncle

  20. Amniotic Cavity Chorion Amnion Allantois Cavity Yolk Sack Allantochorion (Chorioallantois) Cotyledon

  21. Placental Membranes • Yolk Sack • In birds to nourish embryo • In mammal atrophies but source of blood cells and primordial germ cells • Amnion • Non-vascular, fluid filled • Fluid produced by fetus • Protective cushion • Ruptures at birth (not breaking of water)

  22. Placental Membranes (cont.) • Allantois • Blood vessels • Fuses with chorion • Allantochorion or chorioallantois • Brings blood vessels to chorion • Chorion • Outermost membrane • Attachment to mother

  23. Maternal Recognition of Pregnancy

  24. Luteal Regression PGF2a (Bovine, Ovine, Porcine) PGF2a (Equine) No Uterine Factor (human)

  25. CL Status CA • Mechanisms • CL Regression • Luteolytic • No CL support • CL Maintenance • Antiluteolytic • Block PGF2aeffects • Luteotrophic • Stimulate progesterone production by CL (+) Uterine PGF2a CL Filamentous Embryo (+) Maintained

  26. Recognition of Pregnancy • Conceptus Secretions • Proteins • Steroids

  27. Recognition of Pregnancy in Bovine and Ovine • Conceptus Secretions • Interferons • oIFN-t • bIFN-t • Mechanism • Antiluteolytic • Inhibit oxytocin receptor synthesis • Inhibit PGF2a synthesis • Critical Days • Bovine - 16 to 17 • Ovine - 12 to 13

  28. E2 E2 PGF2a E2 PGF2a PGF2a E2 E2 E2 PGF2a Recognition of Pregnancy in the Porcine

  29. E2 E2 E2 PGF2a PGF2a E2 PGF2a E2 E2 PGF2a Recognition of Pregnancy in the Porcine • Conceptus Secretions • Estradiol Critical Days 11 to 12 • Mechanism • Antiluteolytic • Redirect PGF2a • Requires 2 embryos per horn

  30. PGF2a PGF2a • Mechanism • antiluteolytic Recognition of Pregnancy in the Mare • Conceptus Secretion • ? Critical Days 10 to 14

  31. HCG Recognition of Pregnancy in the Human • Conceptus Secretes • HCG • Mechanism • luteotrophic • Critical Days • 8 to 12

  32. RPL Recognition of Pregnancy in Rodents • Estrous cycle - 4 days • Mating induces prolactin • Maintenance of CL • Psuedopregnancy • Not Pregnant • Prl i after day 7 • PGF h day 11 • Estrus by day 17 • Pregnant • RPL h after day 7, h P4 • PGF h day 11 • RPL protects CL from PGF • Luteotrophic • Antiluteolytic

  33. Recognition of Pregnancy INF-t RPL HCG Estradiol • Conceptus Secretions • Proteins • Steroids

  34. Implantantion

  35. Time of Implantation Attachment to Uterus Species Beginning Completion pig 13 24 cow 22 40 sheep 15 28 mare 24 - 40 95 - 100 human 7 - 8 30

  36. Type of Implantation • Superficial • Chorion lies opposed to uterine wall • Farm animals • Eccentric • Chorionic sack in a uterine fold • Rodent • Interstitial • Embryo digests part of uterine wall • human

  37. Degree of Tissue Loss at Parturition • Deciduate • Eccentric, interstitial • Rodent, human • Indeciduate or Nondeciduate • Superficial • Farm animals

  38. Convex Concave Cotelydon (Chorion) Caruncle Endometrium Cotelydonary Placenta Cow Ewe 70 - 120 90 - 100

  39. Placentome Cotelydonary Placenta Cow Ewe

  40. Placental Attachment in Ruminant Binucleate Cell Chorion Migrate and fuse with uterine epithelium Uterine Epithelium Syncytium Capillary Fusion of Binucleate cells and uterine epithelium (multinucleate) Stroma

  41. Day 23 Migration of Bicnucleate Cells and Formation of Syncytium Binucleate Cell Endometrial Stroma Multinucleated Cells in Uterine Epithelium

  42. Binuclear Giant Cells • 20% of fetal placenta • Invade endometrium • Source • Placental lactogen • Pregnancy specific protein B

  43. Placental Lactogens (Protein Hormones) Prolactin-like activity: Stimulates Milk Synthesis NotPresent in Pig and Mare • May regulate maternal metabolism to facilitate fetal growth • High levels in the last 1/3 of gestation. • High levels facilitate higher milk production. • Dairy cows have higher blood concentrations than beef cows

  44. Pregnancy Specific Protein B • Unique to ruminants • 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!!!

  45. Diffuse Placenta Horse Pig Microcotyledons

  46. Microcotelydon(Fetal) Microcotelydon Epithelium Microcotelydon (Maternal) Endometrial Glands Endometrium Uterine Arteries Uterine Veins Microcotelydons Increase placental surface area

  47. Endometrial Cups in Mare • From both trophoblast and endometrium • 5 to 10 • Form between days 35 to 60 • Produce equine chorionic gonadotropin (eCG, PMSG) • Sloughed off after day 60

  48. Zonary Placenta(bitch, queen)

  49. Discoid Placenta(human)

  50. Cell Layers Separating Maternal and Fetal Blood Maternal Fetal Capillary Capillary Endothelium Endothelium Connective Tissue Connective Tissue Chorionic Epithelium Endometrial Epithelium

More Related