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