Placenta and Its Role in Fetal Development
Perhaps one of the most crucial components of the developmental process is the placenta. The placenta is a semipermeable membrane that allows certain substances to travel through to the fetus (ATSDR, 2012). The placenta is crucial to the well-being of the fetus, for it is the organ that mediates the exchange of blood and nutrients from the mother (Rahmalia, 2012). The primary functions of the placenta are to transport nutrients, oxygen, immunoglobulins, and hormones to the fetus, facilitate the elimination of waste products, perform endocrine functions, and prevent the mother’s immune system from attacking the fetus (Rahmalia, 2012).
The healthy placenta does form a barrier for most pathogens and for certain xenobiotic substances. However, it is by design an imperfect barrier since it must transport substances required for growth and development. Placental transport can be by passive diffusion for smaller molecules that are lipid soluble or by active transport for substances that are larger and/or electrically charged. Some toxic chemicals may be actively transported. The dose of a substance received by the fetus is determined by the amount of the substance transported across the placenta as well as the rate of metabolism and elimination of the substance. As the fetus has an immature metabolism, it is unable to detoxify substances very efficiently; and as the placenta plays such an important role in substance exchange between the mother and the fetus, it goes without saying that any toxic substances that the mother is exposed to are transported to the fetus, where they can then affect development. Carbon-dioxide, lead, ethanol (alcohol), and cigarette smoke in particular are all substances that have a high likelihood of placental transferal (ATSDR, 2012).
Identifying potential hazards for fetal development requires a basis of scientific information. In 2004, Brent proposed a set of criteria for identifying causes of congenital malformations that also are applicable to developmental toxicity in general. Those criteria are:
- Well-conducted epidemiology studies consistently show a
relationship between particular effects and exposure to the substance.
- Data trends support a relationship between changing levels of
exposure and the specific effect.
- Animal studies provide evidence of the correlation between substance
exposures and particular effects.
Read more about this topic: Environmental Toxins And Fetal Development
Famous quotes containing the words placenta, role and/or development:
“The past grows gradually around one, like a placenta for dying.”
—John Berger (b. 1926)
“When things turn out pretty much as expected, parents give little thought to how much they have influenced the outcome. When things don’t turn out as expected, parents give a great deal of thought to the role they play.”
—Arlene Harder (20th century)
“I could not undertake to form a nucleus of an institution for the development of infant minds, where none already existed. It would be too cruel.”
—Henry David Thoreau (1817–1862)