<Tr> <Th> TE </Th> <Td> E5. 11.3. 1.1. 0.5 </Td> </Tr> <Tr> <Td_colspan="2"> Anatomical terminology (edit on Wikidata) </Td> </Tr> <P> The placenta is an organ that connects the developing fetus to the uterine wall to allow nutrient uptake, thermo - regulation, waste elimination, and gas exchange via the mother's blood supply; to fight against internal infection; and to produce hormones which support pregnancy . The placenta provides oxygen and nutrients to growing fetuses and removes waste products from the fetus's blood . The placenta attaches to the wall of the uterus, and the fetus's umbilical cord develops from the placenta . These organs connect the mother and the fetus . Placentas are a defining characteristic of placental mammals, but are also found in marsupials and some non-mammals with varying levels of development . The homology of such structures in various viviparous organisms is debatable, and in invertebrates such as Arthropoda, is analogous at best . </P> <P> The word placenta comes from the Latin word for a type of cake, from Greek πλακόεντα / πλακοῦντα plakóenta / plakoúnta, accusative of πλακόεις / πλακούς plakóeis / plakoús, "flat, slab - like", in reference to its round, flat appearance in humans . The classical plural is placentae, but the form placentas is common in modern English and probably has the wider currency at present . </P>

What passes through the placenta from mother to embryo