History of the Samurai. No one is quite sure who the first samurai was. Historians do have some idea of when regular warriors began taking on the characteristics of the samurai. In the 5th, 6th, and 7th centuries, A.D., there were rivalries in Japan between princes and clans, as well as succession wars when an emperor died.
Amniotic fluid is present in the amniotic sac. It is generated from maternal plasma, and passes through the fetal membranes by osmotic and hydrostatic forces. When fetal kidneys begin to function in about week 16, fetal urine also contributes to the fluid. The fluid is absorbed through the fetal tissue and skin. After the 20th-25th week of pregnancy when the keratinization of an embryo's skin occurs, the fluid is primarily absorbed by the fetal gut.
â Realtime, via e-mail. 1  That's two questions, so two answers. 2  Fetal urination is normal. 3  Urine production begins late in the first trimester, about the same time the two-inch embryo becomes a fetus.  Fetal defecation isn't normal, but fetuses do accumulate a mass of greenish feces, called meconium, in their intestines.