Q.Except endocrine function, what are the other functions of placenta.

The placenta is far more than just an endocrine gland. Beyond secreting hormones, it performs several critical roles that sustain the pregnancy and protect the developing foetus.

• Nutritive function: The placenta transports nutrients — such as glucose, amino acids, vitamins, and minerals — from the mother's blood to the foetal blood, ensuring the foetus receives all the building blocks it needs for growth.
• Respiratory function: Oxygen from the mother's blood diffuses across the placental barrier into the foetal blood, while carbon dioxide from the foetal blood moves in the opposite direction to be exhaled by the mother. In effect, the placenta acts as the foetus's lungs.
• Excretory function: Metabolic waste products produced by the foetus (like urea and uric acid) pass from the foetal blood into the maternal blood, from where the mother's kidneys eliminate them. The placenta thus serves as the foetus's kidneys. …

The placenta is a remarkable temporary organ that forms during pregnancy, connecting the developing foetus to the mother’s uterine wall. While its endocrine function — secreting hormones like hCG, oestrogen, and progesterone to maintain pregnancy — is widely discussed, the placenta is far more than a hormone factory. It acts as the foetus’s lungs, intestines, kidneys, and immune shield all in one.

Think of the placenta as a highly selective interface between two separate bloodstreams: the mother’s and the foetus’s. They never mix directly; instead, substances diffuse or are transported across the placental barrier. This arrangement allows the placenta to perform several vital non-endocrine functions.

Nutrient and gas exchange is arguably its most critical job. The foetus cannot eat, breathe, or drink on its own. The placenta delivers oxygen and essential nutrients — such as glucose, amino acids, vitamins, and minerals — from the mother’s blood to the foetal blood. Simultaneously, it removes carbon dioxide and other waste products from the foetal circulation and transfers them back to the mother’s blood for excretion. In essence, the placenta serves as the foetus’s lungs and digestive system.

Waste elimination is the flip side of exchange. The foetus produces metabolic wastes like urea and bilirubin. These are passed across the placenta into the mother’s bloodstream, where her kidneys and liver process and eliminate them. Without this function, toxic waste would accumulate in the foetal environment.

Immune protection is another crucial role. The placenta acts as a physical and immunological barrier. It prevents many pathogens from crossing from mother to foetus, while selectively allowing maternal antibodies (IgG) to pass through. This passive immunity protects the newborn during the first few months of life, before its own immune system matures. …