Stages+of+Embryo

Stages Of Embryo

The first stage of the embryo, is when it is fertilized. To protect the egg from more than one sperm fertilizing it, the egg creates a hard barrier around itself. The DNA encoded information of the egg and sperm combine together to begin dividing within the egg while traveling down the falopian tube into the uterus. This is called a Morula, or a ball of cells. Once it reaches the nucleus, the egg will be very packed together and in a tight space. All of the cells will move outwards creating a hollow cavity in the center called a blastocyst. The cells in the center of the blastocysts will become the baby, but the cells around the inside of the ball will become the support systems and structures for the baby. After a week or so, the blastocyst will stick to the endometrium and bury itself into the lining. After this step, the blastocyst can recieve nutrition from the mom and can continue its development, by this point, Gestation has begun. This is the Gastrula.There are three germ layers in the gastrula. There is the ectoderm layer, which will become the skin and nervous system, the mesoderm layer, which will become most organs including the skeleton, muscles and blood, and finally the endoderm layer which will become the digestive tract, respiratory tract and urinary bladder.

One of the most important structures in the developing child is the placenta, which will provide it with nutrients and support for the next 9 months in the mothers womb. Second to the placenta, the umbilical cord provides nutrients and oxygen to the baby, and gives the mothers wastes and carbon dioxide, this exchange is very risky, because if the blood mixes, then the baby and mother could both die. Also, the amniotic fluid surrounds the baby and protects it. This is produced by both mother and baby. This will make sure the baby will make it through all three trimesters until he/she is born.



In this picture, the baby is going through the first trimester. In the first trimester, the nervous system is the first organ to form, but, the heart is the first organ to form and function, at that young of an age! All other organs begin to form, and the placenta and umblical cord connects the mother and the embryo at this point.

In the second trimester, accesory organs form, like nails, eyelashes and eyebrows. The baby starts to move, it can suck its thumb, and it can kick. At this point in the pregnacy, a doctor can tell if its a boy or girl. The skin is covered in soft hair, and the lungs begin to develop. In the third trimester, the baby starts gaining fat, and very quickly. The skin begins to develop as well. As organs are still developing, the baby is sharping skills, as they can see light and can hear sounds.