Placental cotyledon | |
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Structure of the placenta, with a placental cotyledon marked in rectangle. | |
Gray's | subject #12 63 |
In human development, the cotyledons are the approximately 15-30 separations of the decidua basalis of the placenta, separated by placental septa.[1] Each cotyledon consists of a main stem of a chorionic villus as well as its branches and subbranches etc.[1]
The cotyledons receive fetal blood from chorionic vessels, which branch off cotyledon vessels into the cotyledons, which, in turn, branch into capillaries.[2] The cotyledons are surrounded by maternal blood, which can exchange oxygen and nutrients with the fetal blood in the capillaries.