BGDA Practical Placenta - Placental Functions

From Embryology
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Practical 14: Implantation and Early Placentation | Villi Development | Maternal Decidua | Cord Development | Placental Functions | Diagnostic Techniques | Abnormalities


Term Placenta

Placenta term anatomy 01.jpg

Exchange

Placenta oxygen exchange levels.jpg Placenta spiral artery conversion.jpg
  • oxygen, carbon dioxide, carbon monoxide
  • water, glucose, vitamins
  • electrolytes
  • waste products
    • urea, uric acid, bilirubin.
  • hormones
    • mainly steroid, protein hormones poorly transported.
    • maternal thyroid hormone can slowly cross.
    • fetal insulin can impact on maternal diabetes.
  • maternal antibodies
    • maternal IgG antibodies are transferred from about week 13 (GA) across the placenta
    • from the maternal lacunae syncytiotrophoblast cell endosomes bind IgG through neonatal Fc receptors.
  • drugs and their metabolites (fetal drug addiction)
  • infectious agents (cytomegalovirus, rubella, measles, microorganisms)

Endocrine

Protein and steroid hormones.

  • Human chorionic gonadotrophin (hCG) - like leutenizing hormone, supports corpus luteum in ovary, pregnant state rather than menstrual, maternal urine in some pregnancy testing
  • Human chorionic somatommotropin (hCS) - or placental lactogen stimulate (maternal) mammary development
    • rise through pregnancy, stimulates maternal metabolic processes, breast growth
  • Human chorionic thyrotropin (hCT)
  • Human chorionic corticotropin (hCACTH)
  • Relaxin
  • Steroid Hormones - progesterone (maintains pregnancy), estrogens (fetal adrenal/placenta)

Placental Metabolism

Synthesises - glycogen, cholesterol, fatty acids

  • provides nutrient and energy

Additional Information

Drugs

  • Abnormal Development - Drugs - The placenta and fetal tissues may deal with drugs differently from adult target tissues. In particular, drugs are "cleared", metabolised and excreted, at a different rate in both the fetus and in newborn infants. In general there is a much lower rate of clearance.

<pubmed>21766440</pubmed> <pubmed>21789231</pubmed> <pubmed>19732616</pubmed>| PMC2767264



BGDsmall.jpg
Practical 14: Implantation and Early Placentation | Villi Development | Maternal Decidua | Cord Development | Placental Functions | Diagnostic Techniques | Abnormalities