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week 2
This week the implantation of the human embryo has been completed. Its growth will be very rapid from this moment. The embryo appears in the center, like a bilaminar disk and is located between 2 cavities, the amnion and the yolk sac. On the outside, we find the trophoblast that will form the fetal part of the placenta. -
Week 3 Embryonic stage
The nervous system begins its formation during the third week, when the embryo is formed by three layers of cells: The upper layer, ectoderm from where the brain and several regions of the central nervous system will develop, as well as the epidermis, the glands of the Skin, nails and hair. -
Weak 4 and 5
The basic structure of the body is conformed. The development of the eyes, ears, mouth and nose begins. The buds that will give rise to the arms and legs are observed. Cardiac prominence is very visible. Brain vesicles develop. -
Week 6 and 7
The development of the trachea, larynx and bronchi progresses. The oral and nasal cavity begin to separate, the palate forms. Legs and arms that look like fins develop more. -
Week 8
By the end of this week, the body will be formed, as well as all its organs and the embryonic period will end. It will stop being an embryo to become a fetus. In this week, the fingers and toes grow. The head is disproportionately large and constitutes half of the embryo. The neck region has formed. Its growth in the uterus is facilitated by having a very flexible body; Its skeleton has no bones, but cartilage. -
Week 9 fetal period
Inicia el periodo fetal, que termina hasta el nacimiento. Comienzan a diferenciarse los caracteres sexuales primarios, determinados por la combinación de cromosomas, heredada en el momento de la fecundación. Los huesos empiezan a formarse, así como la lengua. Los ojos aún están cerrados. Los intestinos se encuentran en el cordón umbilical. -
Week 10 and 11
The intestines move towards the abdomen and suffer a rotational movement that puts them in their correct anatomical position. The fingers and toes have been defined. During these weeks, nail development begins. In this phase, the liver is the main organ that produces blood. -
Week 12
Here, the sexual organs have formed and sex can be recognized. Towards the end of this week, the fetus begins to produce and excrete urine into the amniotic fluid. The pancreas starts the production of insulin. He already has chin ears and eyelids. His skin is very thin and transparent. Start moving your limbs. -
Week 13 and 14
It is possible to appreciate its human aspect. the ears are in their final position and the thin eyelids will remain closed until the seventh month. -
Week 15 and 16
The growth is very fast. The vocal cords begin to form. The sense of touch begins to develop. It is able to separate the toes, flex the wrists and close the fists, you can even turn your head and open your mouth. In this period it increases its number of reflexes and is capable of sucking and swallowing. The legs are already longer than the arms and move their limbs frequently. -
Week 17 to 20
Your skin is covered by a greasy material and a thin fluff called lanugo, which protects it from amniotic fluid and possible chafing. Fat is formed in areas near the neck, behind the breastbone and around the kidney. This fatty tissue allows you to generate heat. At the end of this period, in the female fetus, the formation of the vaginal canal begins and in the male, the descent of the testicles from the abdomen to the scrotal bag begins. Start forming fine hair. -
Week 21 and 22
Fetuses are considered viable, when they are able to live outside the maternal organism. Before 22 weeks they generally are not, because their organs have not reached the physiological maturity necessary to have life independently. Length and weight are the most commonly used parameters to calculate fetal age, however, other external characteristics must be taken into account. -
Week 21 to 25
His body is still covered with lanugo and his skin is wrinkled. He already has eyelashes and although his eyes remain closed, the iris is acquiring its color. Start having a tooth outline. The lungs have the ability to expand, so the fetus could breathe outside the uterus, in case of premature birth. -
Week 26 to 29
Your nervous system is able to control respiratory movements and temperature. His movements are more active. Your stomach, intestines and kidneys work perfectly. All your sensory organs are awake. The eyelids and eyes are fully formed and begin to open and close. Start perceiving the sounds. Intense noises increase your heart rate. He gets hiccups. -
Week 30 to 38
It is already in the right position for the time of delivery, in most cases it is with the head down and the buttocks up. Your skull is not yet completely solid, as it needs to pass through the birth canal. Slide your thumb inside your mouth and practice the sucking reflex. At the end of this period, the baby can reach a height of up to 50 cm and an average weight of 3 kg. By the end of week 38, the baby is in a position to be born. -
Week 39 and 40
Dedicate these last weeks to strengthen and gain weight. Less amniotic fluid remains in the uterus. Lanugo hair has almost disappeared. The brain is perfectly constituted. It can differentiate the bitter from the sweet and the sense of smell is activated. His heart beats at a speed of 120-160 beats per minute. The baby is ready for birth. -
Week 1
During the first week fertilization occurs, the union of the female cell with the male. Each one has 23 chromosomes, together they create a 46 chromosome cell that travels from the middle third of the fallopian tube to the uterus, where it will be implanted to begin its development.
