Embryonic development begins from the moment of conception and continues until a person is born. In general, intrauterine development consists of 2 phases: the first two months are embryonic, and the subsequent (3-9) are called fetal. Intrauterine development lasts about 280 days, or 9 months. An embryo in obstetric practice is called an embryo, which develops in the body for about two months, then the embryo is called the fetus.
Embryonic development: from fertilization to birth
The muscular membrane of the epithelium contracts, forcing the egg to move through the fallopian tube towards the sperm, the male reproductive cells. As a result of this, fertilization occurs. Only one sperm can enter the egg, after which a protective membrane appears around it, preventing other sperm from entering. Embryonic development begins from the moment of fusion of two nuclei, forming a certain set of chromosomes. After that, the earliest stages of embryo development begin, which consist of crushing the cell into many small ones.
The baby eats stocks of yolk, which are in the egg. After some time, the fetus enters the uterus and attachment, or implantation, occurs. Already on the 7th day, the baby is gradually introduced into the uterus. After this, the embryo begins to produce chorionic gonadotropin, a hormone that is a signal to the mother about the onset of pregnancy (it is he who ensures the appearance of two stripes on the test).
On days 10-14, the embryo, whose development proceeds at a normal pace, becomes 2 times larger. Further, embryonic development occurs rapidly. The nervous system begins to form already on the 20th day of pregnancy. Three weeks later, the baby's heart beats. At about 28 days, the spine and muscles appear. Using ultrasound, the arms, legs, ears and eyes of the child are visible.
In just 30 days, the baby’s size has increased 10 thousand times, and continues to grow rapidly. Five days after that, the fingers and toes are already distinguishable, the eyes darken, as the baby's body produces a special pigment.
At a period of 6 weeks, the brain begins to control the work of the heart and the movement of the muscles of the embryo. The liver produces blood cells. A week later, the eyelids of the child appear, which protect the eyes from dryness and light. At this stage of pregnancy, the outer and inner ear of the baby is actively formed, the beginnings of the teeth are born and the jaws begin to take shape. However, the most important and significant change is that the little man begins to move in the womb. Unfortunately, he is still too small for his mother to feel these movements.
8 weeks is an important milestone in the development of the baby. At this stage of development, he already looks like a person. Its size is only 2.5 centimeters, and his heart is already beating confidently, his muscles are contracting, his face acquires certain features, and his body reacts to touch. After 2 weeks, the child grows up to 4 centimeters and weighs about two grams. This period is characterized by the formation of the baby's genitals.
At the 12th week, he already sucks his finger and energetically trains his muscles. The kid begins to turn his head, bend his fingers on the handles, open and close his mouth. At this time, the fetus sees and hears, covers its ears with hands in response to sharp sounds and turns away from a bright ray of light. In the period from 16 to 24 weeks, active changes occur, which include the appearance of hairline, cilia. The kid is already smiling, hiccups, and mom feels it distinctly. From the 24th week to the 34th embryonic development is almost complete, the baby is already freely expressing emotions (joy, anger, discontent). He can see dreams. The photos show pouting lips or a smile. 36-38 weeks are the final stage of development of the child. Now he is completely ready to be born.