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How does the placenta and umbilical cord support a mammalian embryo?

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embryos of different animals — Animal development The embryos of many animals appear similar to one another in the earliest stages of development and progress into their specialized forms in later stages.

In mammalian development, the placenta and umbilical cord function as a vital life-support system that connects the developing embryo or fetus to the mother, facilitating essential metabolic exchanges without the direct mixing of their bloodstreams.123

The Role of the Placenta

The placenta is a specialized organ formed from both maternal and embryonic tissues. It acts as the site for:13
* Nutrition and Respiration: Nutrients and oxygen from the mother’s blood diffuse into the fetal blood, while metabolic wastes like carbon dioxide and nitrogenous products diffuse from the fetus into the maternal circulation for disposal.13
* Barrier Function: It maintains a "placental barrier" that separates maternal and fetal blood while allowing for the selective passage of necessary substances, such as antibodies.13
* Endocrine Support: The placenta produces hormones that help maintain pregnancy and regulate fetal development.34

The Role of the Umbilical Cord

The umbilical cord serves as the physical conduit between the fetus and the placenta. It contains two umbilical arteries and one umbilical vein:12
* Umbilical Vein: Carries oxygenated, nutrient-rich blood from the placenta to the fetus.12
* Umbilical Arteries: Transport deoxygenated blood and fetal waste products from the fetus back to the placenta for processing by the maternal body.12