The process of growth and development within the womb, in which a single-cell zygote becomes an embryo, a fetus, and then a baby is known as prenatal development. The process of prenatal development occurs in three main stages. Germinal stage: The first two weeks after the implantation. Embryonic stage: The duration from the third week through the eighth week. Fetal period: The time from the ninth week until birth. During the first two stages of life, it is referred to as the embryo while as it reaches the third stage, the fetal period, it is referred to as the fetus. The fetal period of prenatal development marks more important changes in the brain. This period of development begins during the ninth week and lasts until birth. Implantation is a process in which a developing embryo, moving as a blastocyst through a uterus, makes contact with the uterine wall and remains attached to it until birth.

Describe what happens to each of the following during the birth of a baby. Muscles in the uterus wall. The cervix. The placenta.

Implantation is a process in which a developing embryo, moving as a blastocyst through a uterus, makes contact with the uterine wall and remains attached to it until birth. There are various changes that take place during the time of the birth of a baby. The production of estrogen takes place reaching its peak at the date of birth. Estrogen has a vasodilation effect, increases blood flow to the uteroplacental in preparing for uterine contraction. MUSCLES IN THE UTERUS WALL: The uterus is multi-layered. The oxytocin causes the smooth muscle in the uterine wall to contract. The contractions of these muscles pull on the cervix and help to open it and put pressure on the baby, helping the baby move downward. CERVIX: The enlarged mucus glands of the cervix during pregnancy secretes a mucus plug called the operculum, acts as a seal for the uterus and protects it from ascending infection, and acts as a barrier between the vagina and cervix. PLACENTA: The placenta is an organ that develops in your uterus during pregnancy. This structure provides oxygen and nutrients to your growing baby and removes waste products from your baby's blood. It detaches from the uterine wall after childbirth. In the case of a C-section, the placenta is removed from your uterus during the procedure.