Placenta

Definition

The placenta is a temporary 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, playing a crucial role in fetal development and maternal health throughout gestation. The placenta also produces hormones that support pregnancy and help prepare the body for childbirth.

5 Must Know Facts For Your Next Test

1. The placenta forms from trophoblastic cells of the blastocyst and begins to develop shortly after implantation in the uterine wall.
2. It is responsible for producing hormones like human chorionic gonadotropin (hCG) and progesterone, which are essential for maintaining pregnancy.
3. The placenta allows for selective nutrient transfer, ensuring that essential substances such as glucose and amino acids reach the fetus while filtering out potentially harmful substances.
4. During parturition, the placenta is expelled from the mother's body after the baby is born, a process known as afterbirth.
5. Placental insufficiency can lead to complications in pregnancy, affecting fetal growth and development due to inadequate nutrient and oxygen supply.

Review Questions

• How does the structure of the placenta facilitate its role in nutrient and gas exchange between mother and fetus?
  • The placenta's structure features numerous villi that increase its surface area for absorption, allowing for efficient nutrient and gas exchange. Maternal blood flows around these villi, enabling oxygen and nutrients to diffuse into fetal blood while carbon dioxide and waste products diffuse out. This intimate connection ensures that the fetus receives the essential resources needed for growth while also removing metabolic wastes effectively.
• Discuss the hormonal functions of the placenta and their significance during pregnancy.
  • The placenta produces several key hormones including human chorionic gonadotropin (hCG), progesterone, and estrogen. hCG signals the ovaries to maintain progesterone production, which prevents menstruation and supports early pregnancy. Progesterone helps maintain the uterine lining, while estrogen promotes uterine growth and blood flow. These hormonal functions are vital for creating an optimal environment for fetal development and preparing the mother's body for childbirth.
• Evaluate the potential impacts of placental abnormalities on fetal development and maternal health during pregnancy.
  • Placental abnormalities such as placenta previa or placental abruption can significantly impact both fetal development and maternal health. For instance, placenta previa can cause bleeding complications and necessitate a cesarean delivery, while placental abruption can lead to reduced blood flow to the fetus, increasing risks of growth restrictions or stillbirth. Additionally, these conditions can pose serious health risks for the mother, including hemorrhage and infection, highlighting the importance of placental health in successful pregnancies.

Related terms

Chorion: The outermost membrane surrounding the embryo, which contributes to the formation of the placenta.

Amniotic Sac: A fluid-filled sac that surrounds and protects the developing fetus, providing cushioning and maintaining a stable environment.

Umbilical Cord: A flexible structure that connects the fetus to the placenta, facilitating the transport of nutrients and oxygen while removing waste products.