EVERYDAY SCIENCE

Detailed explanation-1: -The placenta is the organ through which gases, nutrients, and wastes are exchanged between the maternal-fetal circulations.

Detailed explanation-2: -The placenta is a specialized organ of exchange that provides nutrients to and excretes waste products from the fetus.

Detailed explanation-3: -The fetus is dependent upon the placenta for transport to it of all nutrients for energy and growth. The primary nutrients crossing the placenta are glucose, lactic acid, free amino acids, free fatty acids, and ketone bodies. Under normal circumstances, it appears that glucose is the primary energy source.

Detailed explanation-4: -Figure 5.1 The placenta is the organ of respiratory gas exchange for the fetus. It supports the developing fetus by transferring oxygen and nutrients from the maternal to the fetal circulation and transferring carbon dioxide and wastes away from the fetal to the maternal circulation.

Detailed explanation-5: -Arterial blood from the uterine arteries enters the placenta, constituting a lake of arterialized blood. It is in this lake that exchanges take place. Carbon dioxide and waste products come from the umbilical arteries and are exchanged by passive diffusion to the maternal blood.