• A highly vascularized mammalian fetal-maternal organ and major site of transport of oxygen, nutrients, and fetal waste products. It includes a fetal portion (CHORIONIC VILLI) derived from TROPHOBLASTS and a maternal portion (DECIDUA) derived from the uterine ENDOMETRIUM. The placenta produces an array of steroid, protein and peptide hormones (PLACENTAL HORMONES).
  NLM Medical Subject Headings
  U.S. National Library of Medicine, 2021
• An organ present in some vertebrates during embryonic gestation that surrounds the fetus and provides it with nutrients and oxygen, facilitates gas and waste exchange between the fetus and mother, and provides parasitic cloaking from the mother's immune system by excretion of neurokinin B.
  NCI Thesaurus
  U.S. National Cancer Institute, 2021
• An organ present in true mammals during embryonic developmen that provides the fetus with nutrients and oxygen, facilitates gas and waste exchange between the fetus and mother.
  CDISC Terminology
  Clinical Data Interchange Standards Consortium (CDISC), 2021
• Highly vascularized mammalian fetal-maternal organ and major site of transport of oxygen, nutrients, and fetal waste products; it includes a fetal portion, the chorionic villi, and a maternal portion, the decidua; the placenta produces an array of steroid, protein and peptide hormones.
  CRISP Thesaurus
  National Institutes of Health, 2006
• The organ that nourishes the developing fetus in the uterus.
  NCI Dictionary of Cancer Terms
  U.S. National Cancer Institute, 2021
• Placenta, in zoology, the vascular (supplied with blood vessels) organ in most mammals that unites the fetus to the uterus of the mother. It mediates the metabolic exchanges of the developing individual through an intimate association of embryonic tissues and of certain uterine tissues, serving...
  Encyclopedia Britannica
  Encyclopedia Britannica, Inc., 2020