Placental cotyledon
Structure of the placenta, with a placental cotyledon marked in rectangle.
Anatomical terminology

The placenta of humans, and certain other mammals contains structures known as cotyledons, which transmit fetal blood and allow exchange of oxygen and nutrients with the maternal blood.

Ruminants

The Artiodactyla have a cotyledonary placenta. In this form of placenta the chorionic villi form a number of separate circular structures (cotyledons) which are distributed over the surface of the chorionic sac. Sheep, goats and cattle have between 72 and 125 cotyledons whereas deer have 4-6 larger cotyledons.[1][2]

Human

The form of the human placenta is generally classified as a discoid placenta. Within this the cotyledons are the approximately 15-25 separations of the decidua basalis of the placenta, separated by placental septa.[3] Each cotyledon consists of a main stem of a chorionic villus as well as its branches and sub-branches.[3]

Vasculature

The cotyledons receive fetal blood from chorionic vessels, which branch off cotyledon vessels into the cotyledons, which, in turn, branch into capillaries.[4] The cotyledons are surrounded by maternal blood, which can exchange oxygen and nutrients with the fetal blood in the capillaries.

References

  1. ↑ Kurt Benirschke (2007). "Placentation". Retrieved 13 January 2017.
  2. ↑ Erick Conard (2002). "Cotyledonary Placenta: An Easy To Understand Explanation". Retrieved 13 January 2017.
  3. 1 2 Page 565 in: Varney, Helen; Helen Varney Burst; Kriebs, Jan M.; Gegor, Carolyn L. (2004). Varney's midwifery. Boston: Jones and Bartlett Publishers. ISBN 0-7637-1856-4.
  4. ↑ Gordon, Z.; Elad, D.; Almog, R.; Hazan, Y.; Jaffa, A. J.; Eytan, O. (2007). "Anthropometry of fetal vasculature in the chorionic plate". Journal of Anatomy. 211 (6): 698–706. doi:10.1111/j.1469-7580.2007.00819.x. PMC 2375851. PMID 17973911.


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