Placenta

Definition

The placenta is a vital organ that develops in the uterus during pregnancy, serving as the interface between the mother and the developing fetus. It facilitates the exchange of nutrients, gases, and waste products, ensuring that the fetus receives essential substances while removing harmful waste. The placenta also produces hormones that support pregnancy and plays a key role in immune protection for the fetus.

5 Must Know Facts For Your Next Test

1. The placenta forms from both maternal and fetal tissues, with the fetal side consisting of chorionic villi that extend into the maternal blood supply.
2. Hormones produced by the placenta, such as human chorionic gonadotropin (hCG) and progesterone, are crucial for maintaining pregnancy and supporting fetal development.
3. The placenta acts as a barrier to protect the fetus from many harmful substances but is not completely impermeable, allowing some pathogens and toxins to cross.
4. Placental abruption is a serious condition where the placenta detaches from the uterine wall prematurely, posing risks to both mother and fetus.
5. After childbirth, the placenta is expelled from the uterus in a process called placental delivery, marking the end of pregnancy.

Review Questions

• How does the placenta facilitate the exchange of substances between the mother and fetus during pregnancy?
  • The placenta facilitates exchange by providing a large surface area through its chorionic villi, which are bathed in maternal blood. Nutrients and oxygen diffuse from the mother's blood into the fetal blood vessels within the villi, while waste products like carbon dioxide move in the opposite direction for elimination. This efficient exchange ensures that the developing fetus receives everything it needs for growth while also managing waste removal.
• Discuss the role of hormones produced by the placenta and their impact on pregnancy.
  • Hormones produced by the placenta, including human chorionic gonadotropin (hCG), progesterone, and estrogen, play critical roles in maintaining pregnancy. hCG supports early pregnancy by signaling to the ovaries to produce more progesterone, which helps thicken the uterine lining. Progesterone maintains this lining and reduces uterine contractions, preventing premature labor. Estrogen promotes uterine growth and blood flow to support fetal development. Together, these hormones create an optimal environment for a healthy pregnancy.
• Evaluate how placental health affects fetal development and maternal well-being during pregnancy.
  • Placental health is crucial for proper fetal development and maternal well-being. A healthy placenta ensures adequate nutrient and oxygen supply to the fetus, which is essential for growth and development. Issues like placental insufficiency can lead to poor fetal growth or preterm birth due to inadequate nutrient transfer. Additionally, conditions such as gestational diabetes or preeclampsia can affect placental function and lead to complications for both mother and baby. Thus, monitoring placental health is vital for ensuring positive outcomes during pregnancy.

Related terms

Chorion: The outermost membrane surrounding the embryo, which contributes to the formation of the placenta and plays a role in gas exchange.

Umbilical Cord: A flexible cord that connects the fetus to the placenta, containing blood vessels that transport nutrients and oxygen to the fetus while removing waste.

Amniotic Fluid: The fluid within the amniotic sac that surrounds and protects the developing fetus, providing cushioning and facilitating movement.