Placentation Classification of the chorion Chorion frendosum villi
- Slides: 16
Placentation
Classification of the chorion • Chorion frendosum – villi choriales • Chorion laeve – no villi
Allantois • This sac-like structure is primarily involved in nutrition and excretion, and is webbed with blood vessels. • The function of the allantois is to collect liquid waste from the embryo, as well as to exchange gases used by the embryo.
The equine placenta • The equine placenta is classified as diffuse. It involves the entire surface of the chorioallantois except for a small area adjacent to the cervix called the "cervical star", where attachment cannot occur.
Placentation in swine • Pigs have a non-invasive placenta epithelio-chorial and diffuse.
Placentation in Ruminants (Cattle, sheep, . . ) • Ruminants have a cotyledonary placenta. Instead of having a single large area of contact between maternal and fetal vascular systems, these animals have numerous smaller placentae. • The terminology used to describe ruminant placentation is: – Cotyledon: the fetal side of the placenta – Caruncle: the maternal side of the placenta – Placentome: a cotyledon and caruncle together
Dogs, cats
Primates and rodents
Decidual cells of the endometrium
Summary of Species Differences in Placental Architecture
Type of Placenta Common Examples Diffuse, epitheliochorial Horses and pigs Cotyledonary, epitheliochorial Ruminants (cattle, sheep, goats, deer) Zonary, endotheliochori al Carnivores (dog, cat, ferret) Discoid, hemochorial Humans, apes, monkeys and rodents
Developing fetus
Chorion laeve and chorion frondosum
Secondary oocyte
Exemple de drupe
Order
Pear placentation
Flower reproductive parts
Vicario filidei
Surface area of villi
Csf dr
Villi function
Secondary villi
Where is villi located
Amount of csf produced per day
Villi adaptation
Battledore placenta
Primary villi consist of
