1 / 25

FETAL MEMBRANES AND PLACENTA BY

FETAL MEMBRANES AND PLACENTA BY. PROF MASOOD AHMED MBBS, MPHIL PHD. Relative Size of Human Conceptus. Implantation of the Blastocyst. Implantation of the Blastocyst. FETAL MEMBRANES. REFRESH FEW TERMS DECIDUA BASALIS, CAPULARIS AND PARIETALIS VILLI FORMATION

mali
Download Presentation

FETAL MEMBRANES AND PLACENTA BY

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. FETAL MEMBRANES AND PLACENTABY PROF MASOOD AHMED MBBS, MPHIL PHD

  2. Relative Size of Human Conceptus

  3. Implantation of the Blastocyst

  4. Implantation of the Blastocyst

  5. FETAL MEMBRANES REFRESH FEW TERMS DECIDUA BASALIS, CAPULARIS AND PARIETALIS VILLI FORMATION CYTOTRPHOBLASTIC SHELL FORMATION CHORIONIC MEMBRANE PARTS CHORION FURONDOSUM AND CHORION LAEVE AMNIOCHORIONIC MEMBRANE

  6. Embryonic Membranes • Amnion – Epiblast cells form a transparent membrane filled with amniotic fluid • Provides a buoyant environment that protects the embryo • Helps maintain a constant homeostatic temperature • Amniotic fluid comes from maternal blood, and later, fetal urine

  7. CYTOTROPHOBLASTIC SHELL FORMATIONPLACENTAL BARRIER/ MEMBRANE

  8. Embryonic Membranes • Allantois – a small outpocketing at the caudal end of the yolk sac • Structural base for the umbilical cord • Becomes part of the urinary bladder • Chorion – helps form the placenta • Encloses the embryonic body and all other membranes

  9. AMNION WITHIN CHORION

  10. Placentation • The chorion develops fingerlike villi, which: • Become vascularized • Extend to the embryo as umbilical arteries and veins • Lie immersed in maternal blood • Deciduabasalis – part of the endometrium that lies between the chorionic villi and the stratum basalis

  11. UTERO PLACENTAL CIRCULATION –12TH DAY CIRCULATION • 4TH MONTH CHORION FRONDOSUM AND DECIDUA BASALIS • 5TH MONTH DECIDUAL SEPTA AND COTYLEDON FORMATION CONTIOUS FLOW IN INTERVILLOUS SPACE

  12. PLACENTAL SURFACES • FETAL SURFACE • CHORIONIC VESSELLS CONVERGING TOWARDS UMBLICAL CORD • 2-ARTERIES AND ONE VEIN • CHORION COVERED BY AMNION • ECCENTRIC ATTACHMENT OF UMBILICAL CORD • MATERNAL SURFACE • 15-20 COTYLEDONS • Functional type • hemochorial

  13. FULL TERM PLACENTA • 15-20% INNER SURFACE COVERED WITH PLACENTA • ALL THE TIME SYNCITIAL SURFACE SEPARATES THE MATERNAL BLOOD • COTYLEDONS- CORE OF ENDOMETRIAL TISSUE COVERED BY SYNSITIUM • 15-20 IN NUMBER • SHAPE-DISCOID • SURFACE AREA 15-20cm • THICKNESS-3cm • WEIGHT-500-600gms

  14. Placentation

  15. Placenta • 80-100 MATERNAL ENDOMETRIALSPIRAL ARTERIES SUPPLYING VILLI • A TOTAL 150 ML BLOOD IN PLACENTAL CIRCULATION • REPL;ENISHES 3-4 TIMES / MINUTE • PLACENTAL BARRIER • SEPARATES MATERNAL AND FETAL BLOOD • COMPRISED OF • ENDOTHELIAL LINING OF VILLI CAPPILARIES • C.T IN VILLI • TROPHOBLASTIC LAYER • CYTO TROPHOBLAST LAYER • 4TH MONTHS ONWARD • INCREASED EXCHANGE BY • C.T AND TROPHOBLAST LAYER DISAPPEAR • CLOSE TO END OF PREGNANCY • DECREASE EXCHANGE BY • INCREASE FIBROUS TISSUE IN VILLI • FIBRINOID DEPOSIT ON SURFACE OF VILLI • OBLITERATION OF SMALL CAPPILARIES

  16. Variations of placenta • Normally---hemochorial and eccenteric • Variations • velamentous –when umblical vessels divide before and branches come to placenta • Marginal- when umblical vessels join placenta at margin • Succenturiate- when additional small plcental lobe is present or separate small placenta is present • accreta- when placental reaches up to basal layer of endometrium • Increta- when placental infiltrates in the myometrium • Percreta- when placenta infiltrates up to connective tissue and crosses the muscule layer

  17. AMNIOTIC FLUID • SYNTHESIZED BY • CLEAR WATERY FLUID • MAINLY BY • MATERNAL CIRCULATION • PARTLY BY AMNIOCYTES • 30-ML—10TH WEEK • 350 ML—20TH WEEK • 800-1000 ML---37TH WEEK • REPLACED /3-4 HRS • 5TH MONTH ONWARD • SWALLOWING • AND ADDITION OF URIN • FUNCTIONS • ABSORBS JOLTS • ALLOW FETAL MOVEMENTS • HORMONE PRODUCTION • AVOIDS ADHERENCE • Polyhydroamnios • Amount of amniotic fluid • more than 1500 ml eg • Esophageal atresi, anencephaly • Oligohydroamnios • Amount of amniotic fluid • less than 400 ml eg • Renal agenesis

  18. Membranes in twins • DIZYGOTIC OR FRATERNAL twins • Separate amniotic and chorionic membranes and placenta • May be different sex, blood groups, features

  19. Monozygotic twins • If twins form by the division of zygot at two cell stage with the formation of two separate blastocyst • Two Separate amniotic and chorionic membranes and placenta • Features,Sex and blood groups same

  20. If twins form by the division of inner cell mass in blastocyst • Two Separate amniotic cavities • Common chorionic membranes and placenta • Features, Sex and blood groups same

  21. If twins form by the late division of inner cell mass in blastocyst or by division of bilaminar germ disc • Common amniotic, chorionic membranes and placenta • Features, Sex and blood groups same

More Related