Human Development: Prenatal-Toddler The Developing Baby Human Development: Prenatal-Toddler

Conception Ovum: an egg cell Ovulation: an egg cell is released by one of a woman’s two ovaries. Uterus: the organ in a women’s body in which a baby develops during pregnancy. Fallopian Tube: connects the ovary to the uterus. Sperm: male cell. Conception: a male cell reaches the Fallopian tube; it may penetrate and fertilize the ovum.

Prenatal Development Prenatal Development: the baby’s development during a pregnancy. Grouped into three stages: germinal stage, embryonic stage, and fetal stage.

The Germinal Stage Zygote: fertilized egg. Cell Division While the zygote is still in the Fallopian tube, it begins to grow by cell division. Single cell splits into two cells, then the two cells rapidly multiply to four, eight, then so on. Implantation Lining of the uterus has thickened enough to provide a place for the zygote to attach itself and continue to grow. Zygote usually implants in the lining of the uterus and is covered over by that lining. Despite the rapid growth of the zygote during the two weeks after fertilization, it is only the size of the head of a pin. The Germinal Stage

Embryonic Stage Embryo: the developing baby is called from about the third week of pregnancy throughout the eighth week. During this stage that several important and amazing changes occur. Organs and Body Systems The cells begin to separate and develop into the major systems of the human body. 27 days after conception the neural tube, has closed. The developing brain is sensitive to damage from any drugs or alcohol the mother might take.

Embryonic Stage Amniotic Sac Amniotic Fluid: protects the developing baby. Formed from special layers of cells in the uterus. Cushions the embryo from any bumps or falls that the mother might have. Embryo is still very small and can float freely in the amniotic fluid. The Placenta and Umbilical Cord Placenta: formed from special layers of cells in the uterus. It is rich in blood vessels and attached to the wall of the uterus. Umbilical Cord: connects the baby to the placenta. The umbilical cord takes carbon dioxide and other waste products away from the baby and to the placenta, which releases those wastes into mother’s bloodstream.

Fetal Stage Third and final stage of development is the longest. Begins around the eighth or ninth week of pregnancy and lasts until birth. Making Movements During the fourth and fifth month, the kicks and other movements of the fetus touch the wall of the uterus. Can feel similar to fluttering. Gradually, sensations become stronger and more frequent. Completing Development During the last few months of pregnancy, development continues, preparing the fetus to live independently. Body’s major organs become ready to function without and help from the mother’s body. Fetus gains weight rapidly, begins to look more “baby-like.” Fetal Stage

Fetal Stage Staying Active Growing Bigger Fetus can do surprising number of things—suck its thumb, cough, sneeze, yawn, kick and hiccup. Fetus can even cry. Even though the fetus is still very active and can change positions. Growing Bigger The uterus also expands, causing the woman’s abdomen to grow. Fetus grows large during the last few months of pregnancy, no longer has room to stretch out. Fetal Position: fetus curls up inside the uterus.

Preparing for Birth Pregnancy is about 40 weeks, or 280 days, from first day of the last menstrual cycle. Fetus is fully developed and can usually survive outside the mother’s body without a great deal of medical assistance. Some babies are born either a few weeks early or a few weeks late.