This week your baby is no longer considered an embryo, but a fetus. The fetus is now the size of a grape and has doubled in size in the last two weeks. The body parts that have formed up until this point will now begin to become more specialized. This is a very busy developmental period that will last until about 20 weeks.
Right now the fetus is developing teeth and it’s palate. The ears continue to develop, although right now they are located low on the head, and will move up as the head grows. Skin is paper-thin and veins are clearly visible. Fingers and toes are forming now and the arms can flex at the wrists and elbows. The bones for arms and legs begin to harden and joints are forming.
The head has grown quite quickly and is still quite large in comparison to the rest of the body. The hindbrain, which is responsible for breathing, heart regulation and muscle movements, is beginning to develop now.
The critical period in heart development ends now. The heart will continue to develop, but at a much slower pace. Blood has begun to flow through a basic circulatory system. The tubes from the throat to the lungs are now formed.
The intestines are beginning to develop within the umbilical cord. When the body is large enough, they will move into the proper area. Your fetus still has a tail, but it is smaller than in the past, and its entire body is straightening out.