Embryonic tissue is the fertilized egg formed after the union of sperm and egg, the fertilized egg continues to develop and develops into a fetus and its appendages collectively. After the fertilized egg is deposited, it begins to develop, and after ultrasound examination around 40 days of pregnancy, the uterine cavity gestational sac, primitive cardiovascular fluctuations, and fetal buds can be found. With the increase of pregnancy weeks, to about 8 weeks of pregnancy embryo first human form, head large, accounting for half of the entire fetal body. Can distinguish the eyes, ears, mouth, nose, fingers, and toes, each organ began to develop, the heart has been formed, after 8 weeks gestation embryo gradually developed into a fetus. In addition to the fetus, there is also the placenta, umbilical cord and these appendages, and the fetus is collectively referred to as embryonic tissue. If you feel unwell during pregnancy, you should seek medical advice.