The placenta (pl.: placentas or placentae) is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation.

2023年10月26日 · The main function of the placenta is the interchange between the mother and the fetus. More specifically, it provides nutrition and oxygen to the fetus and removes waste material and carbon dioxide. In this article, we will explore …

2011年9月25日 · Two characteristics are particularly divergent and form bases for classification of placental types: The gross shape of the placenta and the distribution of contact sites between fetal membranes and endometrium. The number of layers of tissue between maternal and fetal vascular systems.

What is the placenta? The placenta is a temporary organ that connects your baby to your uterus during pregnancy. The placenta develops shortly after conception and attaches to the wall of your uterus. Your baby is connected to the placenta by the umbilical cord.

2023年5月1日 · Proper development of the placenta is essential for a successful pregnancy. There are several layers of tissue that make up this delicate organ that need to develop normally for proper function during gestation. Without proper function, there can be devastating consequences to the pregnancy.

Placenta villi are composed of three layers of components with different cell types in each: (1) syncytiotrophoblasts/cytotrophoblasts that cover the entire surface of the villous tree and bathe in maternal blood within the intervillous space; (2) mesenchymal cells, mesenchymal derived macrophages (Hofbauer cells), and fibroblasts that are locat...

Within 11 days of fertilization, the trophoblast forms two layers, 1st the cytotrophoblast and 2nd the syncytiotrophoblast, containing lacunae. The placenta forms a barrier to permit exchange of nutrients, gases and wastes with only slight mixing of fetal blood with maternal blood.

2025年2月23日 · In human, the placenta at term is a discoid shape "flat cake" shape; 20 cm diameter, 3 cm thick and weighs 500-600 gm. Placenta are classified by the number of layers between maternal and fetal blood (Haemochorial, Endotheliochorial and Epitheliochorial) and shape (Discoid, Zonary, Cotyledenary and Diffuse).

The placenta is composed of three layers. The innermost placental layer surrounding the fetus is called the amnion (Figure 5-30). The allantois is the middle layer of the placenta (derived from the embryonic hindgut); blood vessels originating from the umbilicus traverse this membrane.

Amnion—innermost layer lined by a single layer of epithelium with underlying connective tissue. Can see squamous metaplasia with hyperkeratosis— incidental finding associated with irritation. Chorion—Composed of connective tissue with fetal vasculature.