Week eight is a milestone in a baby's life. The Micro Magnetic Resonance Imaging based visualization reveals a normal, but oversized looking liver (purple) in the thorax, a fairly defined lung, an already 4 chamber heart that beats now for about 4 weeks. By the end of this week the embryo has distinct human characteristics. Every organ and system is already in place. Developmental in the fetal period needs further differentiation of the organs and tissues and a rapid gain in size and weight.