The placenta is an organ that connects the developing fetus to the uterine wall to allow nutrient uptake, waste elimination, and gas exchange via the mother's blood supply. "True" placentas are a defining characteristic of eutherian or "placental" mammals, but are also found in some snakes and lizards with varying levels of development up to mammalian levels. Note, however, that the homology of such structures in various viviparous organisms is debatable at best and, in invertebrates such as Arthropoda, is definitely analogous at best.

The word placenta comes from the Latin word for cake, from Greek plakóenta/plakoúnta, accusative of plakóeis/plakoúsπλακόεις, πλακούς, "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.

Prototherial (egg-laying) and metatherial (marsupial) mammals produce a choriovitelline placenta that, while connected to the uterine wall, provides nutrients mainly derived from the egg sac.

The placenta functions as a fetomaternal organ with two components: the fetal placenta, or (Chorion frondosum), which develops from the same blastocyst that form the fetus, and the maternal placenta, or (Decidua basalis), which develops from the maternal uterine tissue.

Read more about Placenta:  Structure, Development, Birth, Pathology, Cultural Practices and Beliefs, Additional Images

Other articles related to "placenta":

Placental Disease - Pathology - Adherence/penetration
... Abruptio placentae Placenta accreta Placenta increta Placenta percreta. ...
Cardiapoda - Species - Synonyms
... Cardiapoda acuta (synonym of Cardiapoda placenta (Lesson, 1831) ) Cardiapoda carinata (synonym of Cardiapoda richardi Vayssière, 1903) Cardiapoda pedunculata (synonym of Cardiapoda placenta (Lesson ...
Placinta - History
... of cakes, called the libum and the placenta ... As for the placenta, the Romans developed the recipe as a cake made of fine flour covered with cheese, honey, and fragrant bay leaves ... Ancient Roman bakers customarily prepared a large placenta which was cut into squares to be offered for sale ...
Placenta - Additional Images
... Magnified a little over two diameters Picture of freshly delivered placenta and umbilical cord wrapped around Kelly clamps Fresh human placenta Micrograph of a placental ...
Manual Placenta Removal
... Manual placenta removal is a procedure to remove a retained placenta from the uterus after childbirth ... inserted through the vagina into the uterine cavity and the placenta is detached from the uterine wall and then removed manually ... If the placenta does not separate easily from the uterine surface, there may be a placenta accreta ...

Famous quotes containing the word placenta:

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