2. Fertilization Also referred to as conception. Union of an egg and sperm cell. Fertilization takes place in the Fallopian Tube. How many sperm cells does it take to fertilize and egg ? 1 Within seconds after fertilization the outside of the egg changes.

3. When the sperm and egg unite, they form a Zygote. Within 36 hours, the zygote begins to divide while traveling through the fallopian tubes. It takes 4 to 5 days for the zygote to reach the uterus. No longer solid mass of cell. Now has become a Blastocyst; a hollow sphere. Blastocyst attaches to wall of uterus. This is the process of implantation. After implantation, blastocyst becomes and Embryo.

5. Pregnancy Most common sign, missed menstrual period. Menstruation stops because progesterone levels stay high. Can be determined as soon as implantation occurs. Human Chorionic gonadotropin is found in the blood of pregnant women.

6. The Embryo The attachment holding the embryo to the wall of uterus develops into an organ called placenta. About 25 days after fertilization, a cord called umbilical cord form between embryo and placenta. Umbilical cord is the embryo’s lifeline. Blood vessels that carry oxygen and nutrients to embryo and waste away from embryo.

8. The Fetus Between the 3 rd and 6 th month, the fetus will grow to about 11 inches and weigh up to 2 lbs. “Kicking” shows the sign of skeletal and muscles development. Between the 6 th and 9 th month the fetus continues to grow. Average baby will be 20 inches and weigh about 7.5lbs.