Placenta

(pla-sen'tah,) pl. PLACENTE. [L, a cake. ] (Anat.) A temporary organ that is developed within the uterus during pregnancy, and is, as its popular name implies, expelled from the maternal organism shortly after the birth of the child or young animal. It is a spongy vascular ma , existing in some form or other in all mammals, excepting the Marsupial i a and Monotremata, as an appendage to the fœtal membrane called the chorion. The main function of the P. appears to be like that of the lungs in the adult. It admits of the blood of the fœtus being thrown to that of the mother, and undergoing requisite changes. It may, also, be an organ for nutritive absorption. (Bot.) The place or part on which ovules originate. [s. 713]