CBSE Class 12-science Answered

Functions of human placenta:

1. Nutritive organ: Food materials pass from the mother’s blood into the foetal blood through the placenta.

2. Digestive organ: The trophoblast of the placenta digests proteins before passing them into foetal blood.

3. Respiratory organ: Oxygen diffuses from the maternal blood into foetal blood through the placenta. Carbon dioxide diffuses from the foetal blood into the maternal blood also through the placenta for elimination by the mother’s lungs.

4. Excretory organ: Nitrogenous wastes pass from the foetal blood into the maternal blood through the placenta for elimination by mother’s kidneys.

5. Endocrine organ: Placenta secretes (hCG), estrogen, progesterone and human placental lactogen.

6. Storage organ: The placenta stores glycogen for the foetus before liver is formed.

7. Barrier: Many substances pass from the mother to the foetus via placenta and cause abnormal development in the developing foetus.