DOMINANT FOLLICLE DEVELOPMENT
Every month, a group of eggs (oocytes) from the ovarian reserve are selected and begin to develop in preparation for ovulation (release of the egg). The egg develops in a small fluid-filled cyst (follicle).
Normally, only one of this group is selected to complete its development (dominant follicle).
The dominant follicle prevents the development of the other ovaries with which it sets out and the others. they
destroy themselves. Meanwhile, in the week following menstruation, the estrogen hormone stimulates the inner lining of the uterus (endometrium) and turns it into a bed where the vascular structures expand and gland secretions increase.
WEEK 2: OVULATION br /> Progesterone hormone increases and matures the egg in the fluid-filled sac (follicle). The maturing
follicle cracks and releases the egg inside from the ovary (ovulation). Ovulation often occurs 2 weeks before the start of the next
menstrual period. It continues the production of progesterone from the structure formed in the place of the ruptured follicle (corpus
luteum). Progesterone prepares the inner lining of the uterus (endometrium)
for nesting (implantation). There is a protective cell
layer around the egg leaving the ovary. The egg is caught by the finger-like protrusions of the tubes and begins to move inside the tube. It waits to be fertilized by a sperm within 12-24 hours following ovulation. Fertilization occurs approximately 2 weeks after the first day of the last menstrual period. During ovulation, the cervical secretion
becomes fluid and facilitates the passage of sperm. The sperm pass through the uterus and reach the tubes. Even though there are 200-600 million sperm in male ejaculate, only about 200 reach the tubes.
FERTILIZATION
Sperms secrete chemicals (enzymes) to pass the protective outer layer of the egg. The changes that occur when a
sperm enters the egg prevent the entry of another
sperm through the membrane surrounding the egg. During fertilization, your baby's entire genetic structure, including gender, is determined and complete.
If Y sperm fertilizes the egg, it will be a boy; if X sperm fertilizes it, it will be a girl.
ZYGOTE
Congratulations! Fertilization has just occurred, but you are already 2 weeks pregnant. And the fertilized egg
is now a 'zygote'. fertilization has occurred From the moment of birth, the 'human chorionic gonadotropin' (hCG)
hormone begins to appear in the mother's blood. HCG is produced by the baby's partner (placenta) and is the hormone checked in the pregnancy
test. However, for it to increase enough to be detectable, 3 -
4 weeks must pass after the first day of the last menstrual period.
3. WEEK: NESTING (IMPLANTATION)
Within 24 hours following fertilization, the fertilized egg (zygote) begins to divide rapidly and becomes a blastocyst
. The blastocyst travels through the tube for another 3 days and reaches the uterus. It gets rid of the protective layer around the uterus and comes into contact with the inner lining of the uterus (endometrium) and attaches there with the help of many hormones (implantation). Sometimes during this stage, there may be light bleeding for 1-2 days.
The inner lining of the uterus thickens and the cervix is closed with a plug (mucus).
EMBRYO - FETUS
Within three weeks following fertilization, the blastocyst , turns into a small ball. The first nerve cells
have already formed. This structure formed in the first 8 weeks of pregnancy is called 'embryo'. From the 9th week until birth, it is called 'fetus'.
TRIMESTER
The developmental processes of pregnancy are called 'trimester'. There are distinctive
changes in each period.
4TH WEEK
The embryo is the size of a poppy seed and is surrounded by the amniotic sac. The amniotic fluid in the amniotic sac protects the fetus like an airbag. The baby's placenta and umbilical cord are at the beginning of their
development. The 'yolk sac' nourishes the embryo until the 10th week, when the placenta begins to fully produce its own hormone. Cells migrate towards the 'primitive streak' in the middle to form the embryo.
WEEK 4: THREE LAYERS
Cells migrate towards the 'primitive streak' in the middle. It migrates and forms three
layers in which all organs and tissues will develop:
1. Outer layer: A 'nerve tube' consisting of a cavity begins to form. The brain, spine, spinal cord and nerves will develop from this tube. In addition, ears, eyes, connective tissue, skin, hair and nails
also develop from this layer.
2. Middle layer: Skeleton, muscles, heart and circulatory system, kidneys and reproductive organs.
It develops from the layer.
3. Inner layer: � Internal organs (lung, intestine, bladder) develop from this layer.
5. WEEK
The embryo is the size of a sesame seed; It looks more like a tadpole than a human. It is in the shape of a ball of cells with an upper, lower, front and back side, resembling the letter C-
. While the fetus is protected by the amniotic fluid in the amniotic sac, it is also connected to the yolk sac, which produces blood cells for the embryo. The slit that appears on his back will close in the future and turn into the nerve tube that will form the spinal cord. At this stage, the tube has a wide and
flat top. The brain will also develop from here. The nerve
tube that will connect the brain and spinal cord has formed. The bulge that appears in the middle of the embryo will turn into a U-shaped tube
that will form the heart. The first organ to develop and start working is the heart. The heart consists of a single chamber and its beat rate is 100/minute. On the outer part of the embryo, the buds of the limbs begin to appear. Below the opening that will form the mouth
, small pleats appear where the neck and lower jaw will develop. The embryo is about to enter the rapid
growth phase.
WEEK 6
The embryo is the size of a lentil and is shaped like the letter C. The heart begins to become four-chamber and its heart rate is 150/min, meaning it beats twice as fast as you. The head is larger than the body. Facial
lines are formed: there are black dots in place of the eyes, nostril openings, small
indentations in place of the ears. Vocal cords and tongue also begin to form. Limb buds become evident and continue to
elongate. Muscle and bone tissue is formed. The skin covering it is transparent. The neural tube, where the brain, spinal cord,
nerves and vertebrae will develop, closes. This space will turn into a system that will produce the 'cerebrospinal fluid' that will protect the brain and spine in the future. Folic acid, which is started before pregnancy and recommended to be taken in the first 12 weeks
, prevents developmental anomalies of this system by 85%.
WEEK 7
The embryo is the size of a blackberry and the head-rump distance is 1 cm. . This week is the beginning of a very intense development
process. Organs such as the brain and heart, which form in the first weeks, become more unique and complex. The fetus grows very rapidly from this week to the 20th week.
The head constitutes one third of the body. The brain grows by 1/3. Y Our area is also growing rapidly. Teeth, nasal holes, palate and ears are formed. The eyes are still in the early developmental stage; The lens begins to
form; Transparent eyelids partially cover the eye.
The coccyx appears and there is a small tail that is an extension of it. The arms lengthen,
they take a shape similar to a shovel. Shoulders, upper and forearms and hands become more prominent. Cartilage
is developing in the limbs. Nerves run along the legs. Even though you don't feel it, the fetus is moving like a jumping bean.
8. WEEK
This week is the end of the 'embryonic period', the early period of human development. The head-rump distance of the embryo is 1.6 cm; It is the size of a bean. Brain nerve cells begin to branch and form neural networks with each other. Thus, brain wave activity begins. The olfactory area begins to develop.
Lungs begin to form. Facial features become more and more distinct; The upper jaw, upper lip and nose
are shaped. The arms are extended so that the hands meet in front of the heart. The legs also continue to grow.
However, the arm and leg joints (knees, elbows, wrists) are not yet evident. Fingers begin to form in a webbed
manner. The tail in the embryo has almost disappeared. The coccyx
bone will develop in its place. Body posture begins to straighten. It begins to move imperceptibly.
WEEK 9
Fetal development process begins. The fetus is the size of a grape: 2.3 cm., 2 gr. The tail part has disappeared.
It looks more like a human. Bones are developing in the arms. The arms are bent at the elbows. Hands
begin to touch the face and legs begin to move. Wrists and ankles are more developed. The web-like appearance of the fingers disappears and the fingers become more distinct and begin to be distinguished. The pinna
is now prominent. Hair roots begin to form. Taste sensory cells begin to appear on the tongue. Milk teeth
bulges appear. The external genital area begins to form. The nipple is formed. The hiccup reflex
begins. The placenta now produces its own hormones.
WEEK 10
The fetus is the size of an olive: Head-rump distance is 3.1 cm., weight: 4 gr. Since there is no need for the yolk sac, it begins to regress. The placenta now produces its own hormones. A. The skin is temporarily
puffy. The outer ear is fully developed; the chin always rests on the chest; The eyelids are completely
closed and will open after the 27th week. The heart is fully developed; It beats 3 times faster than adults. The skin is less
transparent. Nails are developed and begin to lengthen. Arms and legs make a rotation
movement from the shoulders and hips. The fetus is small but actively moving. Abdominal muscles begin to develop. Makes breathing movements from time to time. Reproductive organs begin to form.
11TH WEEK
The fetus is the size of a fig: Head-rump distance is 4.1 cm. Almost all organs and body structures
have been formed and begin to function. The fetus is actively moving. Fingers are now selected separately.
The distinction between boys and girls begins in the external genital organs. Subcutaneous veins are developing and are visible through the skin.
The mouth is almost completed, the palates are fused together, and the roots of the milk teeth
are growing. Tooth sockets begin to appear in the mouth.
12. WEEK
The fetus is the size of a lime: Head-to-rump distance is 5.4 cm., weight: 14 gr. He starts to look more like
human. At the end of the third month, the fetus is fully formed. It has all its organs and limbs and will continue to develop to become functional
. The circulatory system and urinary tract are working. The liver begins to produce bile
. The intestines herniated through the belly button return to the abdomen. Reproductive organs are also
developing, but gender cannot yet be determined by ultrasound. Arms, hands, fingers, feet are fully
developed. He can make fists with his hands. He can open and close his fist. There is a suction reflex. Nails
begin to develop. The skeletal structure consists of cartilage, but it also slowly begins to ossify. Ossification will continue until the twenties. The eyes move closer to the middle. The auricle
begins to take shape. Since your baby has completed the most critical development period, the risk of miscarriage has now decreased.
WEEK 13
The fetus is the length of a pea pod: 7.4 cm., and weighs 23 gr. weighs. The head constitutes one third
of the body. The nose and lips are fully formed. The original lines of the face have appeared. The unique fingerprint
begins to form, but will be completed by the 17th week. Sucking reflex is well developed, head
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