The term intra uterine environment is used to describe the environment inside a mother's womb or uterus. The intra uterine environment is the place where all prenatal development occurs. There are three stages of prenatal development. There is the zygote period, the embryonic period and the foetal period. It is crucial that development takes place at the right time during these three periods, because if they don't, there may be complications with the mother's pregnancy.
The first period is the zygote period, also known as the germinal period. This is the period when the single-celled zygote is created at conception. When the zygote is formed, mitosis divides it in to two identical cells within 12-15 hours of conception. By about the third day, the cells will have divided in to many cells to form a small ball called a blastocyst. The blastocyst then enters the uterus and implants itself in to the uterine lining. This takes place between the seventh and ninth day of conception. In the second week, the inner cell mass of the blastocyst structure separates in to three layers. The outer layer is called the ectoderm, which will later form the skin, hair, sweat glands, tooth enamel, salivary glands and all nervous tissue, including the brain. The middle layer is called the mesoderm, which will form the muscles, bones, blood, circulatory system, teeth, connective tissues and the kidney. The inner layer is called the endoderm. The endoderm forms most internal organs such as the stomach, intestines, liver, lungs and the heart. .
The next period is the embryonic period. This period takes place during the third week of conception. After the blastocyst has been implanted in to the uterus, a row of cells begins to form inside the cell mass. The cells begin to roll in to a tube, and form the neural tube, which is the beginning of the embryo. At one end of the neural tube, a mass of tissue begins to form the head and the brain area of the embryo.