Structure and Function of Placenta

PLACENTA IS A ADDITIONAL STRUCTURE THAT DEVELOPS DURING PREGNANCY TO PROVIDE NOURISHMENT TO FETUS.

1. PREPARED BY: Srujani Swetasina Dash NURSING TUTOR G.N.M.INSTITUTE, A.N.M.M.C.H, GAYA Placenta

2. Objectives Definition Characteristics Development Structure Diagram Function Conclusion Bibliography

3. Definition Structure developed in a pregnant uterus through which the fetus derives nutrition. Placenta establishes connection between mother and fetus through the umbilical cord.

4. Characteristics Discoid Hemochorial Deciduate

5. Development Begins at 6 th week of gestation. Completed by 12 th week. Two sources- Chorion Frondosum (fetal component) Decidua Basalis (maternal component)

6. Structure at term Shape : Circular Disc Diameter : 15-20 cm Thickness : 2.5cm at its centre Thins off towards edge Weight : About 500gms at term Proportion :1:6 (weight of placenta: weight of baby) at term Attachment : Upper part of body of uterus near cornua . Invasion : Grows/invades upto decidua compact and Nitabuch’s membrane prevent further invasion into deeper layer. Separation : Occurs after birth through the line of decidua spongiosum . Surfaces :2 surfaces and a peripheral margin Fetal and Maternal

7. contd Presents 2 surfaces (fetal and maternal) and a peripheral margin Fetal surface- Covered by smooth and glistening amnion Umbilical cord attached to it at centre Umbilical vessels visible beneath amnion 4/5 th is fetal origin Maternal surface- Rough and spongy Dull red colour 15-20 polygonal cotyledons limited by fissures 1/5 is maternal origin

8. Fetal surface Maternal surface Diagram of placenta

9. A human placenta

10. Functions Transfer of nutrients and oxygen: Fetus derives nutrients and oxygen from placenta. Excretion: Waste products from fetus is excreted to maternal blood in placenta. Secretion: Produces hormones such as HCG, progesterone etc and enzymes such as oxitocinase necessary to maintain pregnancy. Barrier: Act as protective barrier to fetus against noxious agent. Immunological: Provides immunological protection to fetus.

11. Conclusion Placenta is a vital structure and the knowledge on its structure helps in detecting the abnormalities thereby saving the life of mother and the baby.

12. Assignment Observe the structure of placenta in the labour room and write down the observations. Draw the structure of placenta , attachment of placenta.

13. Bibliography Dutta D.C, “Textbook Of Obstetrics”, New Central Book Agency(P)LTD, 6 th edition, Pg.28-29 Jacob Annamma , “A Comprehensive Textbook of Midwifery”, Jaypee Brothers Medical Publishers(P)LTD, 2 nd edition, Pg.75-78 Myles, “ Textbook for Midwives”, Churchill Livingstone Publishers, 13 th edition, Pg.143-147

14. EVALUATION Class Test – 15 marks for 5 minutes after end of session I. Fill in the blanks: 10×1= 10 Diameter of Placenta is______________. The fetal component of placenta is called as _________________. Placenta is developed from ______________ part of blastocyst . Development of placenta begins from ___________ weeks. Cord is attached to ______________ surface of placenta. Ratio of weight of placenta with fetus is ____________. Maternal component of placenta is called as _____________. The characteristic of placenta is ___________, ______________ and ___________. II. List out the functions of placenta. 5

15. ANSWER KEY I. Fill in the blanks: Diameter of Placenta is 15-20 cm . The fetal component of placenta is called as chorion frondosum . Placenta is developed from trophoblast part of blastocyst . Development of placenta begins from 6 weeks. Cord is attached to fetal surface of placenta. Ratio of weight of placenta with fetus is 1:6 . Maternal component of placenta is called as decidua basalis . The characteristic of placenta is discoid , hemochorial and deciduate . II. List out the functions of placenta. Transfer of nutrients and oxygen. Secretion Excretion Barrier Immunological

16. Thank You