To: Wharf Rat who wrote (24293 ) 8/21/2012 1:37:10 PM From: gamesmistress Read Replies (1) | Respond to Sigh. I said "fetus". That first picture looks like a fertilized egg or an embryo to me. The differentiation happens pretty fast. What are those other pictures? LMP ). At right is a fetus 8 weeks after fertilization (i.e. 10 weeks LMP).ectopic pregnancy , not having passed through in the oviduct (fallopian tube) successfully. This embryo is about five weeks old (or from the 7th week of pregnancy).endometrium ). When it comes into contact with the endometrium it performs implantation . Implantation connections between the mother and the embryo will begin to form, including the umbilical cord . The embryo's growth centers around an axis, which will become the spine and spinal cord. The brain, spinal cord, heart, and gastrointestinal tract begin to form. [2] Week 4–5 Chemicals produced by the embryo stop the woman's menstrual cycle . Neurogenesis is underway, showing brain activity at about the 6th week. [3] The heart will begin to beat around the same time. Limb buds appear where arms and legs will grow later. Organogenesis begins. The head represents about one half of the embryo's axial length, and more than half of the embryo's mass . The brain develops into five areas. Tissue formation occurs that develops into the vertebra and some other bones. The heart starts to beat and blood starts to flow. [2] Week 6–8 Myogenesis and neurogenesis have progressed to where the embryo is capable of motion, and the eyes begin to form. Organogenesis and growth continue. Hair has started to form along with all essential organs. Facial features are beginning to develop. At the end of the 8th week, the embryonic stage is over, and the fetal stage begins. [2]
