The reproductive system

The reproductive system produces specialized cells

The female reproductive systemTwo functions: to produce egg cells, and to protect and nourish the offspring until birth.
Ovaries: two reproductive organs which contains egg cells.
The pituitary gland releases a hormone that stimulates some of the eggs to develop and grow.
The ovaries produce hormones that get the uterus ready to receive the egg.

Menstruation
After egg fully develops-> hormone signals to release the egg->egg moves to a fallopian tube->uterus-> fertilization occurs or menstruation occurs.

The male reproductive system
coiled tubes inside testes produces sperm which is a single cell with chromosomes (head) and tail.
The production of offspring includes fertilization, pregnancy, and birth.
Fertilization
1. Egg is released from ovary.
2. Fertilization occurs
3. Fertilized egg begins to divide.
4. Dividing egg continues down fallopian tube.
5. Embryo moves towards the uterus.

Pregnancy
The nine months of pregnancy can be divided into three periods
2 weeks- embryo grows rapidly, placenta develops
8 weeks- embryo becomes a fetus
12 weeks- bones of fetus develop further

Labor and Delivery
The three stage labor- muscular contractions of the uterus->fetus is pushed out->delivery of the placenta.
-The identical twins are produced when a single fertilized egg divides in half early in embryo development. Each half then forms one complete organism or twin.