3.11 Placenta

3.12 Describe the role of the placenta in the nutrition of the developing embryo.

- The unborn child as an embryo is unable to breathe, digest or excrete. So the child obtains all of these things through the placenta.

- The embryo has an umbilical cord which travels out towards the lining of the uterus and spreads out to form the placenta. The placenta grows into the lining of the uterus, however biologically it is not part of the mother. it grows out of the embryo, not the mother, so the blood vessels (artery's and veins) inside the placenta are the child's.

- Seeing as the placenta grows into the lining of the uterus it is close to the mothers blood stream. The mother will have glucose, amino acids and fats in her blood stream so some of these cross over into the placenta and travel up the umbilical cord and into the child. These things will go from the mothers blood to the child's blood. This is made more efficient by the adaptations of the placenta including a large surface area and thin walls.

- So the nutrients a child obtains during embryo development come from the mother. As well as this the child produces molecules like carbon dioxide and urea which are sent in the opposite direction and excreted through the mother.