Conception, placenta, af, umbilical cord

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  • 1. CONCEPTION AND IMPLANTATION Dr P.L Sankhwar MS, FICOG, FICS Associate Professor, Department of Obst.& Gynae., KGMU, Lucknow.

2. REPRODUCTIVE PHASE IN A WOMAN - Cyclical change in the reproductive organs. - Purpose: 1.To render an Oocyte available for fertilization Ovarian cycle Follicular phase- Ovulation- Luteal phase 2.Prepare uterus for implantation of the fertilized ova. Menstrual cycle- Proliferative phase- Secretory phase- menses or conception. 3. GAMETOGENESIS Oogenesis & ovulation Spermatogenesis & spermiogenesis Oogenesis - process involved in the development of a mature ova. Ovulation Release of ova from the ovary is k/a ovulation. 4. Germ cells Oogonia Primary Oocyte Arrested first meiotic division (up to puberty) Maturation of Graafian follicle Completion of lst meiotic division Secondary Oocyte(23,x) Ist Polar Body(23,X) Ovulation Not fertilized (Degenerates) Fertilized OOGENEIS Completion of second meiotic division Second polar body (23,X) Female pronucleus(23,X) 5. Maximum Number of oogonia 20 wks - 7 mill. At birth 2 mill. At puberty 4 Lakhs Ovulation in whole life- 400 Ova OOCYTE 130 Micron Largest cell of the body. Haploid no. of chromosomes. 6. OVULATION Definition What causes ovulation? Changes in G.follicle & formation of Corpus luteum Changes in oocyte and its maturation Flat epith Cuboidal epith Multi layered Cavity appear mature ova ovulation 7. OVULATION Hypothalamus pulsatile GnRH release FSH & LH (anterior pituitary) (Ovary) G. Follicle Estradiol I. Proliferative changes in endometrium II. Inhibits FSH secretion. III. Stimulates LH secretion. Secrete Estrogen peaks 48 hrs prior ovulation. LH surge 24- 36 hrs prior ovulation. LH causes dominant follicle to rupture & form C. luteum Secretes progesterone --- secretary changes in endometrium --- Inhibit LH secretion. If no conception FSH & LH Decline & Hypothalamus gets positive feedback to secrete GnRH. C. Luteum starts degenerating on 8th post ovulatory day. - shrinks ----- C. albicans ----- C atreticum 8. FERTILISATION 9. DEVELOPMENT OF EMBRYO Zygote formation Morula formation Blastocyst formation 10. IMPLANTATION (NIDATION) Imbedding Changes at implantation site Changes in endometrium Formation of Chorionic villi 11. IMBEDDING Microvilli appear on the surface of trophoectoderm which interdigitate with decidual cells to form junctional complexes. Uterine receptivity is induced by progesterone - LIF - Prostaglandin - Cox- 2 Lysis of stromal cells by histolytic action of blastocyst cells it gets burried more & more deeper in the endometrium and erode the blood vessels Synticium becomes continuous with the endothelium Maternal blood collected into the lacunae Further embedding is stopped by maternal immunological factor and entry point is sealed by fibrin clot. 12. CHANGES IN ENDOMETRIUM (DECIDUA ) Structural and secretory activity in endometrium increased (Decidual reaction). Stromal Fibrous changed into epitheloid decidual cells. Glands show marked tortuousity & dilatation. Endometrium Uppermost Compact layer Intermediate Spongy layer (plane of cleavage during parturition). lower most thin basal layer. After implantation Decidua basalis Decidua capsularis Decidua parietalis 13. PRODUCTS OF CONCEPTION Fetus Umbilical cord Placenta Fetal membranes ( chorion and amnion) Amniotic fluid (liquor amnii) 14. DEVELOPMENT OF PLACENTA Primary villi Secondary villi Tertiary villi 13th days 16th days 21st days 15. DEVELOPMENT OF PLACENTA Principally fetal origin- Chorionfrondosum with some maternal component- Decidua basalis. Start developing in 6th week and completed by 12th week of fertilization. Till 16th week placenta grows in all direction but later on it grows circumferentially Dimension 4th month at term Diameter 80-85 mm 200 mm Thickness 18 -21mm 20 -25mm 16. ESTABLISHMENT OF FETOMATERNAL CIRCULATION 17. PLACENTA At Term oval or circular cake like measuring 6 to 8, 1 thick at center and weighing about 1 pound. Two surfaces (maternal and fetal),10 to 15 cotyledens. Placental barrier (thickness- .025mm)- constituting double layered chorionic epithelium by a layer of stroma and by the fetal capillary wall in first half of pregnancy.and which gets attenuated and now becomes .002mm having a layer of syncytium a mere film of stroma and fetal capillary endothelium. Fetal surface Maternal surface 18. Respiration Food Absorption Excretion FUNCTIONS ABNORMAL PLACENTATION Placenta previa Placenta accreta 19. ABNORMAL PLACENTA 20. UMBILICAL CORD Connect body of fetus with the placenta Its earliest appearance as ventral stalk When fully formed it contains 1.Ventral stalk 2.Umbilical blood vessels (two arteries and one vein) 3.Allantois 4.Vitelline duct and the obliterated extra-embryonic coelom and Whartons Jelly (gelatinonus embryonic connective tissue) At term, cord length varies from 5 to 60 average being 18 to 24, vessels almost always twisted and attaches with the placenta somewhere between center in edge - Eccentric attachment 73%, Central - 18% battledore- 7% and velamentous in 1-2%. 21. LIQUOR AMNII Appears within amnion gradually increases until a term it amounts to approx. 600 ml. (range 300 to 1200 ml). Clear pale fluid, low specific gravity, hypotonic. COMPOSITION - Content mg/100ml Protein 100-500 Sugar 10-60 Chloride (NaCl) 560-660 Sodium 280-310 Non protein nitrogen 20-40 Suspended Matters like lanugo hair, epidermal scales, cells derived from the amniotic epithelium and vernix caseosa also present in it. Abnormal content- glucose , bilirubin, blood, meconium. 22. INDICATIONS FOR AMNIOCENTESIS Diagnostic- - Rh in compatibility - To know fetal maturity - chromosomal analysis - enzyme analysis in metabolic disorders - Estimate alfa-fetoprotein in suspected neural tube defect. Theraputic - Hydramnious - Intrauterine transfusion