Physiology of Placenta in Mammals | Vertebrates | Chordata | Zoology
Placentation is the mechanism by which the foetal and maternal blood circulations are brought very close together for conducting various metabolic functions such as respiration, excretion and nutrition of foetus. In all histological types of placentae, there exists a placental barrier which may include two to six kinds of tissues. Due to the placental barrier, the blood of foetus and [...]