What are the functions of extraembryonic membranes in embryonic development?
Extraembryonic membranes support embryonic development by facilitating nutrient transfer, waste removal, gas exchange, and protection. They include the amnion, which cushions the embryo; the chorion, involved in gas exchange; the yolk sac, providing nutrients; and the allantois, which handles waste and contributes to gas exchange.
How do extraembryonic membranes differ among various animal species?
Extraembryonic membranes differ among animals: in birds and reptiles, they consist of the amnion, chorion, yolk sac, and allantois, supporting embryo development and waste management; in mammals, especially placental mammals, the membranes adapt to form the placenta and other structures crucial for nutrient exchange and fetal protection.
How do extraembryonic membranes contribute to nutrient transfer in pregnancy?
Extraembryonic membranes, primarily the placenta, facilitate nutrient transfer by serving as an interface between the mother and the developing fetus. They enable the exchange of oxygen, nutrients, and waste products via the umbilical cord, ensuring the fetus receives essential sustenance for growth and development throughout pregnancy.
What roles do extraembryonic membranes play in immune protection during pregnancy?
Extraembryonic membranes, including the amnion and chorion, serve as physical barriers that protect the embryo from pathogens. They also produce immunosuppressive molecules that modulate the maternal immune response, preventing the rejection of the fetus. Additionally, these membranes facilitate the exchange of nutrients and waste, supporting a favorable environment for fetal development.
What are the components of extraembryonic membranes in humans?
The components of extraembryonic membranes in humans are the amnion, chorion, yolk sac, and allantois.