What is the common term for the sac that holds the developing fetus in a woman’s uterus?

The sac that holds the developing fetus in a woman’s uterus is commonly referred to as the amniotic sac. This structure is a fluid-filled membrane that surrounds and protects the fetus during pregnancy. It plays a crucial role in providing a cushioning environment and maintaining a stable temperature, which is essential for the developing fetus. The fluid within the amniotic sac, known as amniotic fluid, allows for fetal movements and acts as a barrier against infections.

In contrast, the placenta is an organ that develops in the uterus and serves the vital functions of transferring nutrients and oxygen to the fetus while removing waste products. The uterine wall provides the structural foundation and support for the pregnancy but does not form a sac around the fetus. The cervix is a passageway that connects the uterus to the vagina and plays a role in childbirth but is not involved in encasing the developing fetus. Understanding these differences highlights the specific purpose of the amniotic sac in the context of fetal development.