1. Human Growth and Development

3. Zygote
When a sperm carrying half the necessary DNA combines with an egg containing half the necessary DNA combine a zygote forms. A zygote contains all of the genetic information (DNA) necessary to become a child. The zygote undergoes mitosis until a ball of cells is formed.

6. Blastocyst
In a few days a ball consisting of an inner group of cells and an outer shell is formed. This ball is called a blastocyst.
The inner cells will become
the fetus. The outer shell will
become the membranes that
nourish and protect the fetus.

8. Embyro
The cells begin to differentiate (take on specific functions – types of cells that make up a human being) some form blood cells, others form nerve, bone, etc.
These first few weeks are when a
developing child is most at risk
from what the mother takes into
her system.

10. Embryo 1st week
Embryo has moved from the fallopian tubes to the uterus where it attaches to the uterine wall.
The placenta and umbilical cord will grow and connect the fetus to the mother. This will be the fetus’s only source of food, water, and oxygen.

12. Embryo First 3 to 5 weeks
The heart, brain and spinal cord have already begun to develop.

14. After about 8 weeks the embryo is considered a fetus
Most of the organs and main body parts
have begun to develop and can be clearly seen here.

16. 10 to 32 weeks 10 weeks 12 weeks 32 weeks
Eyes aren’t complete until about 24 weeks.

18. Were you paying attention?
What is a fertilized egg called? ________________
In a ________________ the inner cells become the ____________ the outer layer of cells become the membranes (placenta/amniotic sack) that nourish and protect the fetus.
At how many weeks is the embryo considered a fetus? _________
Where are eggs usually fertilized? ___________________

19. What two things connect the fetus and the mother providing food, water, and oxygen to the fetus? ________________
This is a thin but tough bag that surrounds the fetus protecting it and holding in the fluid that surrounds the fetus. ________________
When do the eyes finish forming? ___________