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Placenta.ppt
- 1. DR REKHA KHARE MD RADIOLOGY The Placenta
- 2. Placenta • The placenta is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation • The placenta is an organ that develops in the uterus during pregnancy. • This structure provides oxygen and nutrients to a growing baby. It also removes waste products from the baby's blood • The placenta attaches to the wall of the uterus, and the baby's umbilical cord arises from it.
- 3. Types of placenta • Posterior placenta: The placenta grows on the back wall of uterus • Anterior placenta: The placenta grows on the front wall of uterus closer to bladder • Fundal placenta: The placenta grows at the top of uterus • Lateral placenta: The placenta grows on the right or left wall of uterus
- 4. Development of placenta • The placenta begins to develop upon implantation of the blastocyst into the maternal endometrium, very early on in pregnancy at about week 4 • The outer layer of the late blastocyst, is formed of trophoblasts, cells that form the outer layer of the placenta. • This outer layer is divided into two further layers: • the underlying cytotrophoblast layer and the overlying syncytiotrophoblast layer. • The syncytiotrophoblast is a multinucleated continuous cell layer that covers the surface of the placenta. • The placenta grows throughout pregnancy
- 5. Placenta • The placenta grows throughout pregnancy. Development of the maternal blood supply to the placenta is complete by the end of the first trimester of pregnancy week 14
- 6. Placental circulation • Placental circulation- maternal and fetoplacental circulation • maternal blood flow begins between days 5– 12, and is approximately 600–700 ml/min at term.
- 7. Feto-placental circulation • Deoxygenated fetal blood passes through umbilical arteries to the placenta. At the junction of umbilical cord and placenta, the umbilical arteries branch radially to form chorionic arteries. • Chorionic arteries, in turn, branch into cotyledon arteries. • In the villi, these vessels eventually branch to form an extensive arterio-capillary-venous system, bringing the fetal blood extremely close to the maternal blood; but no intermingling of fetal and maternal blood occurs • ("placental barrier") • Endothelin and prostanoids cause vasoconstriction in placental arteries, while nitric oxide causes vasodilation. • On the other hand, there is no neural vascular regulation, and catecholamines have only little effect.
- 8. Feto-placental circulation • The fetoplacental circulation is vulnerable to persistent hypoxia or intermittent hypoxia and reoxygenation, which can lead to generation of excessive free radicals. This may contribute to pre-eclampsia and other pregnancy complications. • It is presumed that melatonin plays a role as an antioxidant in the placenta.
- 9. Pathology of placenta • Placenta accreta, when the placenta implants too deeply, all the way to the actual muscle of uterine wall (without penetrating it) • Placenta praevia, when the placement of the placenta is too close to or blocks the cervix • Placental abruption, premature detachment of the placenta • Placentitis, inflammation of the placenta, such as by TORCH infections
- 10. Placenta accreta • Findings could be— • focal thinning or absence of the myometrium at the site of placental implantation • a nodular interface between the placenta and the uterus • a mass effect of the placenta on the uterus causing an outer bulge, heterogeneous signal intensity within the placenta
- 11. Placenta increta and percreta • Placenta increta is a condition where the placenta attaches more firmly to the uterus and becomes embedded in the organ's muscle wall. • Placenta percreta is a condition where placenta attaches itself and grows through the uterus and potentially to the nearby organs (such as the bladder).
- 12. Placenta accreta
- 13. Placenta accreta on USG
- 14. Placenta accreta on USG
- 15. Placenta previa • During pregnancy, the placenta provides the growing baby with oxygen and nutrients from the mother's bloodstream. • Placenta previa means the placenta has implanted at the bottom of the uterus, over the cervix or close by, which means the baby can't be born vaginally.
- 16. Placenta previa
- 17. Types of placenta previa
- 18. Placental abruption • The placenta is an organ that develops in the uterus during pregnancy. • Placental abruption occurs when the placenta separates from the inner wall of the uterus before birth • Placental abruption can deprive the baby of oxygen and nutrients and cause heavy bleeding in the mother.
- 20. Cause of placental abruption • The cause is unknown in most cases, • But risk factors may include maternal high blood pressure, abdominal trauma and substance misuse
- 21. Types of placental abruption 1. Subchorionic abruption - bleeding between myometrium and placental membranes. 2. Retroplacental abruption - bleeding between myometrium and placenta 3. Preplacental abruption - bleeding between placenta and amniotic fluid 4. Intraplacental abruption.
- 22. HAVE A NICE DAY THANKS