1. ANATOMY OF PLACENTA PLACENTAL BARRIER1

2. INTRODUCTION Placenta is a remarkable organ
Has a relative short life span, it undergoes rapid growth ,differentiation and maturation.
A unique fetal –maternal communication system which creates a hormonal environment that helps initially to maintain pregnancy and eventually initiates the events leading to parturition

3. The human placenta is:
Discoid
Hemochorial
Deciduate
Larynthine

5. Implantation is complete on 10 or 11th postovulatory day
On the 7th day ovum
Cytotrphoblast
Syncytiotrophoblast

6. Development of Placenta
Ovum
Morula
Blastocyst

9. Nitabuch’s layer
Placenta on 21 day of gestation – vascularised villous organ
The region of fibrinoid degeneration where the trophoblasts meet the decidua is calld nitabuchs layer.
This layer is absent in placenta accreta

10. Primary villi
Secondary villi
Tertiary villi

14. During this period there is some regression of the cytotrophoblastic elements in the chorionic plate and in the trophoblastic shell where cytotrophoblastic columns degenerate and largely replaced by fibrinoid material –Rohr’s layer

15. PLACENTA AT TERM:
Placenta is a discoid organ
15 – 20cm in diameter
3cm Thick at center
Weighs about 500gms

16. AT TERM
MATERNAL SURFACE

17. FETAL SURFACE

18. Aging of placenta

19. Placental membrane Total area-4 to 14 sq m
Similar to absorbtive area in adult git
In later part of pregnancy the membrane thickness reduces from mm to0.002mm
Is classified as haemochorial

20. FETAL MEMBRANES
2 LAYERS:
Outer chorion
Inner amnion

21. Chorion Internally attached to amnion by loose areolar tissue
Externally covered by trophoblastic layer and decidual cells of fused decidua capsularis and parietalis

22. Amnion
Internal surface is smooth and shiny and in contact with liquor amnii
Outer surface consists of a layer of connective tissue
Amnion can be peeled off from the fetal surface of the placenta except at the insertion of the umbilical cord.

23. Hypertension

24. Development of membranes and formation of amniotic fluid
On the 8th and 9th postovulatory day
Endoderm
Ectoderm
Amniotic cavity
Primary yolk sac
Parietal extra embryonic mesenchyme
Visceral extra embryonic mesenchyme

26. Amniotic fluid 12 weeks:50ml 16 weeks:150ml 38 weeks :900-1000ml
At term : ml
Clinical applications
Composition of amniotic fluid
functions

28. Placental circulation
Uteroplacental circulation
Circulation in the intervillous space
Feto-placental circulation

33. PLACENTAL BARRIER
Inspite of close proximity , there is no mixing of the maternal and fetal blood.
They are separated by placental membranes or barrier.

34. In early pregnancy it consists of:
Syncytiotrophoblast
cytotrophoblast
Basement membrane
Stromal tissue
Endothelium with fetal capillary wall
Its about mm thick

36. Near term.. Attenuation of syncytial layer
Sparse cytotrophoblast and distended capillaries fill the villus.
Vasculo- syncytial membrane: is the specialised zone of villi where the suncytiotrophoblast is thin and anuclear
These alphazones are for gas exchange.
Betazones of terminal villi are for hormone synthesis

37. BARRIER FUNCTION
Fetal membrane is a protective barrier to the fetus against noxious agents circulating in the maternal blood.
Antigen and antibody can traverse through the placental barrier
The race of drug transfer is increased in late pregnancy

38. Maternal infections caused by :
Virus
Bacteria
Protozoa , is transmitted to the fetus by crossing the placental barrier.

39. Placental functions Simple diffusion Facilitated diffusion
Active transfer
Endocytosis
Exocytosis
Respiratory functions
Excretory functions

40. Nutritive function
Enzymatic function
Barrier function
Immunological function
Hormones

41. Hormones produced by placenta
HCG
HUMAN PLACENTAL LACTOGEN
CHORIONIC ADRENOCORTICOTROPIN
RELAXIN
PARATHYROID HORMONE RELATED PROTEIN
GROWTH HORMONE RELATED VARIENT
HYPOTHALAMIC LIKE RELEASING HORMONE
GONADOTROPIN RELEASING HORMONE
CORTICOTROPIN RELEASING HORMONE

42. Clinical aspects of placenta
Multiple pregnancy

45. Placenta praevia Normal sites of implantation of ovum
Upper uterine segment
Abnormal sites of implantation of ovum
Types of placenta praevia
First degree
Second degree
Third degree
Fourth degree

47. Placental abruption

48. Bleeding following premature separation of normally situated placenta
Incidence: 0.49 to 1.8%
Types :
concealed :20 to 35%
revealed : 65 to 85%

49. Gestational trophoblastic disease
Proliferative abnormality of trophoblast associated with pregancy
Persistance GTD = GESTATIONAL TROPHOBLASTIC NEOPLASIA

50. Classification Hyaditiform mole complete partial Invasive moles
Placental site trophoblastic tumors
Choriocarcinoma
Non metastatic disease confirmed to uterus

51. Chorionic villi sampling (CVS) &placental biopsy
Indications :
Prenatal diagnosis of genetic disorder throughout gestation

52. Procedure

53. PLACENTAL TRANSFER Drugs that doesn’t cross placenta:
Heparin large molecule highly polar
Curare

54. Teratogenic drugs Anticonvulsants Phenytoin: cleft lip /palate
Microcephaly
Hypertelorisum
Fingernail hyperplasia
Sodium valproate:
Neural tube defects

55. Lithium
Ebstein’s anomaly
Warfarin
Chondrodysplasia punctate
Microcephaly
Aspleenaia
Diaphragmatic hernia

56. Diethyl stil bestrol
Adenocarcinoma of vagina
Danazol
Virulization of female

57. Retinoids
Crainofacial
Cardiac
Thymic
Cns

58. Thank you