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In placental mammals, the umbilical cord (also called the navel string, [1] birth cord or funiculus umbilicalis) is a conduit between the developing embryo or fetus and the placenta. During prenatal development , the umbilical cord is physiologically and genetically part of the fetus and (in humans) normally contains two arteries (the umbilical ...
The fetal circulation is composed of the placenta, umbilical blood vessels encapsulated by the umbilical cord, heart and systemic blood vessels. A major difference between the fetal circulation and postnatal circulation is that the lungs are not used during the fetal stage resulting in the presence of shunts to move oxygenated blood and ...
The placenta (pl.: placentas or placentae) is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation.It plays critical roles in facilitating nutrient, gas and waste exchange between the physically separate maternal and fetal circulations, and is an important endocrine organ, producing hormones that regulate both maternal and fetal ...
The amniotic sac and its filling provide a liquid that surrounds and cushions the fetus. It is a site of exchange of essential substances, such as oxygen, between the umbilical cord and the fetus. [9] It allows the fetus to move freely within the walls of the uterus. [citation needed] Buoyancy is also provided.
The amniotic membrane and its contents form the umbilical cord that connects the embryo and the placenta. [3] [4] The root of the connecting stalk contains the allantois as a diverticulum of hindgut endoderm along with umbilical vessels. [5] [2] Anomalies are usually referred to as body stalk anomalies and occur in approximately 1 in 15,000 ...
The embryo is joined to the trophoblastic shell by a narrow connecting stalk that develops into the umbilical cord to attach the placenta to the embryo. [11] [15] Arteries in the decidua are remodelled to increase the maternal blood flow into the intervillous spaces of the placenta, allowing gas exchange and the transfer of nutrients to the ...
Placenta with attached fetal membranes (ruptured at the margin at the left in the image), which consists of the chorion (outer layer) and amnion (inner layer).. The part of the chorion that is in contact with the decidua capsularis undergoes atrophy, so that by the fourth month scarcely a trace of the villi is left.
In live bearing mammals, the placenta forms after the embryo implants into the wall of the uterus. The developing fetus is connected to the placenta via an umbilical cord. Mammalian placentas can be classified based on the number of tissues separating the maternal from the fetal blood. These include: endotheliochorial placentation