Question #3ed62
1 Answer
The placenta is a unique organ for allowing exchange of nutrients(food), gases (oxygen and carbon dioxide) and hormones between the fetus(unborn offspring) and the mother.
Explanation:
In humans, the placenta averages 22 cm (9 inch) in length and 2–2.5 cm (0.8–1 inch) in thickness, with the center being the thickest, and the edges being the thinnest. It typically weighs approximately 500 grams (just over 1 lb). It has a dark reddish-blue or crimson color. It connects to the fetus by an umbilical cord of approximately 55–60 cm (22–24 inch) in length, which contains two umbilical arteries and one umbilical vein.
Vessels branch out over the surface of the placenta and further divide to form a network covered by a thin layer of cells. In humans, the placenta usually has a disc shape, but size varies vastly between different mammalian species.
The placenta grows throughout pregnancy. Development of the maternal blood supply to the placenta is complete by the end of the first trimester of pregnancy (approximately 12–13 weeks).
The placenta also provides a reservoir of blood for the fetus, delivering blood to it in case of hypotension and vice versa.
