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2/12/09
2
ANATOMICAL RELATIONS
Moore & Persaud: The developing human- Clinically oriented embryology
EMBRYOLOGY
2/12/09
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PLACENTAL CIRCULATION
Moore & Persaud: The developing human- Clinically oriented embryology
FETAL SURFACE
2/12/09
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HISTOLOGY: PLACENTAL DISC- MATERNAL SURFACE
Moore & Persaud: The developing human- Clinically oriented embryology
HISTOLOGY: VILLOUS ARCHITECTURE
2/12/09
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HISTOLOGY: VILLOUS ARCHITECTURE
Moore & Persaud: The developing human- Clinically oriented embryology
FUNCTIONS OF THE PLACENTA
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PLACENTAL HORMONES
Human Chorionic Gonadotropin (HCG)
• Secreted by SyncytiotrophoblastS • Structurally similar to pituitary LH
• Prolongs survival of Corpus luteum, thus maintaining steroid hormone levels in pregnancy.
• Detectable in maternal plasma 7-10 days after implantation
• Levels peak at 8-10 weeks’ gestation
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Human Placental Lactogen (HPL)
• A.K.A Chorionic Somatomammotropin
• Secreted by Syncytiotrophoblasts
• Structurally similar to pituitary Growth Hormone and Prolactin
• Metabolic effects- Insulin antagonist
• Promotes breast development
PLACENTA IN STEROID HORMONE BIOSYNTHESIS
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PROGESTERONE
• Synthesized by the placenta using maternal cholesterol and LDL lipoprotein
• Serves as a substrate pool for fetal adrenal gland production of glucococorticoids and mineralocorticoids
• Acts to decrease myometrial activity, constrict myometrial vessels, inhibit prolactin secretion,help suppress maternal immunologic response to fetal antigens
Estrogen
• Estrone, estradiol, estriol
• DHEAS- estriol precursor derived from the fetus
• Acts to enhance myometrial activity, promote myometrial vasodilatation, increase pituitary secretion of prolactin
• Maternal serum levels of estriol are decreased in Trisomy 21
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OTHER PLACENTAL HORMONES
• Placental Prolactin
• Placental Thyrotropin
• Placental ACTH and CRF
• Placental growth hormone
• Other peptides- Activin, inhibin, follistatin, urocortin, leptin, IGF etc.
HCG Elevated in Tri 21 uE3 Decreased in Tri 21 AFP Decreased in Tri 21 Inhibin A Elevated in Tri 21
AFP is elevated in Neural Tube Defects
Fetoplacental hormones and peptides in prenatal screening
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DEVELOPMENTAL PATHOPHYSIOLOGY
ECTOPIC IMPLANTATION
Moore & Persaud: The developing human- Clinically oriented embryology
2/12/09
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PLACENTA PREVIA & PLACENTA ACCRETA
Moore & Persaud: The developing human- Clinically oriented embryology
MECHANICAL PROBLEMS MECHANICAL
PATHOPHYSIOLOGY
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CORD KNOTS & TWISTS
CORD: VELAMENTOUS INSERTION
Kaplan: Color atlas of gross placental pathology.
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Listeriosis
Placental Microabscesses
Villous necrosis
Heavy growth of Listeria in postmortem cultures
TRANSPLACENTAL (TORCH) INFECTIONS
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Maternal Vascular Pathology: Pre-eclampsia
Maternal vascular pathology: Placental Infarct
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Maternal vascular pathology: Placental Abruption
PROLIFERATIVE / NEOPLASTIC
PATHOPHYSIOLOGY