During intra uterine life, which of the following organ is not dependant upon the placenta
(Lung) (177-1B. Singh 8lh)Functions of Placenta1. The placenta enables the transport of oxygen, water, electrolyte and nutrition (in the form of carbohydrates, polypeptide, amino acids, and vitamins) from maternal to fetal blood. A full term fetus takes up about 25 ml of oxygen per minutes from the maternal blood. Even a short interruption of oxygen supply is fatal for the fetus.2. It also provides for excretion of carbon dioxide, urea and other waste products produced by the fetus into the maternal blood.3. Maternal antibodies (IgG gamma-globulins) reaching the fetus through the placenta give the fetus immunity against some infections (eg. Diphtheria and measles)4. The placenta acts as a barrier and prevents many bacteria and other harmful substances from reaching the fetus, however most viruses (including poliomyelitis, measles and rubella) and some bacteria can pass across it. Drugs taken by the mother may also enter the fetal circulation and can produce congenital malformations. As a rule, maternal hormones do not reach the fetus. However, synthetic progestins and synthetic oestrogens (eg. Diethylstilbestrol) easily cross the placenta, and can have adverse effects on the fetus(including carcinoma in later life)5. While permitting the exchange of several substances between the maternal and fetal blood, it keeps these blood streams separate, thereby, preventing, antigenic reactions between them.6. The placenta synthesizes several hormones. These are probably produced in the syncytiotrophoblast* The source of oxygenated blood is not the lung but the placenta (262-IBS) only a small portion of this blood reaches the lungs, and passes through it to the left atrium. The greater part is short circuited by the ductus arteriosus into the aortaVesselRemnant(a) Umbilical arteries(b) Left umbilical vein(c) Ductus venosus(d) Ductus arteriosusMedial umbilical ligamentsLigamentum teres of the liverLigamentum venosumLigamentum arteriosum
Liver
Lung
Kidney
Brain
Embryology