How does the placenta connect to the fetus?

The umbilical cord serves as the crucial connection between the placenta and the fetus. It acts as a lifeline, facilitating the transfer of oxygen and nutrients from the placenta to the developing fetus while simultaneously allowing for the removal of waste products. The umbilical cord is composed of blood vessels, typically two arteries and one vein, that transport blood to and from the fetus. As the fetus grows within the amniotic sac, the umbilical cord is essential in bridging the fetal circulation with the maternal circulation, ensuring proper nourishment and growth throughout pregnancy.

In contrast, other connections mentioned do not fulfill the same functional role. The placenta, while directly interfacing with the fetus through the umbilical cord, does not connect directly without this structure. The amniotic sac provides protection and a fluid environment for the fetus but does not play a role in the transfer of nutrients or waste. Lastly, the uterine walls support the placenta but do not serve as a connection for nutrient transfer; they are more about anchoring the placenta in the uterus. Thus, the umbilical cord is uniquely important for the physiological and developmental needs of the fetus.