The sperm and the egg have discovered each other in the Fallopian tube. A unique human being has been created with 46 chromosomes which will determine the person's physical characteristics. Since the third week, the heart has been beating. The neural tube has enlarged into parts which will become the brain. The spine and spinal cord give the appearance of a tail.
Facial features become visible.
The eyes have a retina and lens. The major muscle system is developed and the unborn child begins to move. Blood cells are produced by the liver. The unborn child is half an inch long. The baby is protected by the amniotic sac where the baby swims and moves.