A Theory for the Evolution of the Hemochorial Placenta.

Placenta abruptio (premature separation of the placenta) and placenta praevia (implantation of the placenta low in the uterine segment or over the internal os of the cervix) account for approximately 2% of pregnancy-related emergencies in macaques (Mahoney et al., 1979) and other species.

The study of the placenta is often difficult for pathologists. The terminology of the placental structures alone presents unusual terms, and its development and contribution to fetal life are difficult topics. They are not often taught and can best be understood by approaching the topic from a comparative understanding of the placental development.

The placenta can be classified by the number of membranes (layers of tissue of both maternal and fetal origin) that separate the maternal and fetal circulatory systems in the placental barrier region. This yields four types of placentas: epitheliochorial, synepitheliochorial, endotheliochorial and hemochorial.

Discuss the placental classification based on distribution of attachment sites. diffuse (pig, horse) cotyledonary (cow, sheep) zonary (carnivores). epitheliochorial placenta. Which placenta is histologically classified as having the trophoblasts directly in contact with endometrial CT; having eroded away the uterine epithelium.

Ruminants basically have an epitheliochorial placenta, but because the uterine epithelium is modified by invasion and fusion of binucleate cells, its structure is generally referred to as synepitheliochorial. Prior to detailed study of these structures, it was thought that the maternal epithelium was eroded away, leaving trophoblast in contact with maternal connective tissue.

The syndesmochorial type is a placenta from which the endometrial epithelium is removed after implantation and was added to the placental classification list for a while 14. However, electron microscopic examination eliminated this type from the classification because it is never found in the interhemal regions 15.

This classification is based on the layers between fetal and maternal blood. At a cross-section, two different internal struc-ture types can be visible, villous or labyrinthine. The macaque placenta and the human placenta have been classified as villous. In contrast to a labyrinthine placenta, in which fetal blood.

The anatomic structure of the chorioallantoic placenta in eutherian mammals varies between different animal species. The placental types in eutherian mammals are classified from various standpoints based on the gross shape, the histological structure of the materno-fetal interface, the type of materno-fetal interdigitation, etc. Particularly, the histological structure is generally considered.

Placenta praevia is the medical term for a low-lying placenta or a placenta which is low down in the womb. While fairly common in pregnancy, it could have an impact on your birth plan. Shreelata Data, a Consultant in Obstetrics and Gynaecology, gives us her expert opinion on everything you need to know about placenta praevia.

In the nondeciduate placenta, the fetal components interlock with relatively intact uterine tissue, from which they separate without much loss of endometrium. Epitheliochorial placentation (ungulates) is an example of nondeciduate placentation.

Placenta accreta denotes an abnormal placental adherence onto, into, or through the uterine wall, either partial or total, which leads to difficulty in delivery of the placenta. Additionally, postpartum bleeding may occur because the retained placenta fragments interfere with uterine involution.

Difference between epitheliochorial and endotheliochorial placenta - 9273459.