Fertilisation

1. A mature egg cell is released by one of the ovaries and travels along a fallopian tube.

2. One of the sperm travelling up the fallopian tube joins with the egg cell.

3. Fertilisation takes place. The fertilised ovum is called a zygote.

4. The zygote divides many times and forms an embryo. The process is called cell division.

5. The embryo attaches itself to the wall of the uterus. It now receives oxygen and nutrients.