TITLE:
Accessory Placental Structures—A Review
AUTHORS:
Rennan Lopes Olio, Luis Miguel Lobo, Márcio Aparecido Pereira, Amilton Cesar Santos, Diego Carvalho Viana, Phelipe Oliveira Favaron, Maria Angelica Miglino
KEYWORDS:
Placental Areola, Chorionic Girdle, Placental Hematoma, Hemophagous Organs, Subplacenta
JOURNAL NAME:
Open Journal of Animal Sciences,
Vol.4 No.5,
October
24,
2014
ABSTRACT: Many studies have reported on the different types of placenta in different species, but accessory or paraplacental structures are mentioned only in species that have such a nutrient-exchanging mechanism. Hystricomorph rodents possess a subplacenta, swine and equines have the placental areola, equines have the chorionic girdle, and carnivores have hemophagous organs that are equivalent to the placental hematoma in ruminants. These accessory structures are specialized tissues for specific nutrient exchanges in different species, and they are adaptive modifications exhibited by domestic and wild species to remedy the nutritional deficiencies that are related to permeability of the main placenta to important nutrients for the growth and development of the fetus during the gestation.