Functions of Placenta

 Functions of placenta

The primary function attributed to placenta is the interchange of material present in the blood streams of the mother and embryo. The main functions performed by the placenta are described below.

1. Nutrition :- The nutritive material such as carbohydrates, proteins, fats and inorganic salts along with H,O are passed through placenta from mother's blood to foetus.

2. Respiration :- The placenta also acts as an organ of respiration because the oxygen supplied by the mother diffuses into the foetal blood while carbon dioxide is released in reverse direction This is done in the placenta in a way similar to lung.

3. Excretion :- The fluid waste-products resulting from the metabolic activities of embryo are passed out through the placenta acting like a kidney.

4. Barrier :-  As the placenta is impermeable to some particular matter, the bacteria and larger molecules are not allowed to enter the foetal blood stream. Some substances are allowed to pass while some others are not, so this barrier is known as selective barrier.

5. Synthesis :-  Some substances such as hormones (estrogen, progesterone, gonadotrophin) and some enzymes are manufactured and embedded in the placenta.

6. Immunity :- Placenta is a barrier for several substances and bacteria however, it allows certain antibodies developed in the blood of mother against diseases like measles, small pox diptheria, scarlet fever etc. to pass from maternal blood to the blood of foetus, thereby favouring passive immunity to develop in foetus.

7. Tranport of pathogens :- Placenta does not allow pathogens to pass through however, fails to prevent the entry of pathogenic viruses causing smallpox, measles, chickenpox, syphilis etc. If mother gets infection during pregnancy the foetus may develop congenital deformities.