Fertilization!
The ultimate function of the reproductive system is the creation of a new human being.
Like everyone on earth, we all began our existence as a microscopic cell:
A fertilized egg!
This microscopic cell is formed when a spermatozoon from your father is united to an egg of your mother at the level of the fallopian tubes.
From there, this microscopic cell will migrate to the mother's womb, where practically immediately it will begin to divide, again and again!
Little by little your body will start to take shape.
After nine months in this dark and warm universe, protected inside your mother's body here you are!
Let's see ...
The egg!
The egg is transported from the ovary along the fallopian tubes.
The Trip...
Spermatozoa ejaculated from the penis will swim to the uterus Passing through the neck.
The encounter!
A spermatozoa will come to fertilize the egg inside the fallopian tubes!
After the union, division!
The fertilized egg begins to divide rapidly, it is the phenomenon of mitosis!
The leech you've been ...
The fertilized egg is now a hollow ball of cells, which will attach itself to the wall of the uterus, like a leech to begin its growth.
Packing is weighting!
A bag called the placenta will form around the baby.
The mother will feed the baby through a tube, the umbilical cord attached to the placenta!
Our first meals were taken with straw and directly in our little "can"!
And the baby grows ...
The pregnancy...
During pregnancy, the mother goes through many physical and physiological changes.
At first, the baby takes just a little space, but at the end, it completely "fills" the uterus, exerting pressure, a push against the mother's diaphragm and stomach!
Her heart will pump more blood to feed and let grow her baby!
She eats more to feed him, and her breast grows in preparation for breastfeeding.
The baby is called "embryo" the first eight weeks of its existence.
It will be called "fetus" after that, and this until its birth.
The baby develops in a "padded" envelope filled with a clear liquid called the amniotic fluid.
The fetus swallows this fluid, absorbs it into its bloodstream and evacuates it thereafter.
From the embryo to the baby!
At eight weeks
At eight weeks, the embryo measures 3cm and weighs almost 3gr.
His brain develops at full speed as well as the sensory organs that are not yet operational.
The days that follow are essential for the constitution of his eyes and his inner ears responsible for hearing but also for balance.
The main organs: liver, kidney, heart, lungs are now constituted.
His face continues to develop, his tongue and nostrils have appeared.
The jaws meet and form the mouth.
The salivary glands make their appearance.
The eyelids are fully formed, but they will not open until much later, during the 6th month.
The retina and the lens are formed, the optic nerve works.
Technically speaking, baby is already equipped to see!
His intestines begin to form.
The external genital organs are not yet differentiated.
The circulatory system is made up, and the kidneys begin to make urine which will ultimately form a large part of the amniotic fluid.
Fingers and toes are already identifiable.
His heart rate has normalized around 80 beats per minute, thanks to increased pumping capacity.
We now distinguish the right heart and the left heart.
Ten weeks have passed since the beginning of the last menstrual period, and thus ends the second month of pregnancy!
At twelve weeks
Because of the growth of the uterus, the belly curves begin to appear.
At this point, your heartbeats are still intense and your breathing is more intense.
The hormones of pregnancy slow down the movements of the intestinal muscles,causing a certain intestinal laziness which is accompanied by stomach pains, bloating, difficulties to digest...
Regarding the baby, the fingers of his hands and feet are distinct but not totally separate.
The eyelids develop; The face begins to adopt human traits; And the jaw is ready to accommodate the 20 milk teeth.
The nails and hair begin to grow.
Its marrow and liver produce blood cells.
At the end of the third month, the skeleton and all internal organs are formed, and most are already functioning.
The fetus measures about 10cm and weighs nearly 40gr.
It is possible to hear the beating of his heart through a probe.
If it is a boy, his penis is formed, and it is sometimes visible in ultrasound.
Its first reflexes also appear, as the nervous system matures.
The baby is already beginning to move gently inside the uterus, even if the mother does not perceive it yet.
He also begins to move his hands.
The temperature in the uterus is always a little warmer than your body temperature, a third or a half degree higher.
By controlling your own body temperature, baby never gets cold.
In addition to thermal exchanges via the uterine wall, the temperature of the fetus is mainly regulated by the blood flow coming from the placenta.
The very large exchange surface of the placenta allows it to act as a heat regulator,
keeping constant the temperature of the baby's blood flowing through the umbilical artery and the oxygenated blood returning to the baby via the umbilical vein.
At sixteen weeks
From Mama's side, nausea normally disappeared, the features of her face were rounded, as her stomach began to appear.
Her heart rate is accelerating by about 20% to deal with a greater blood flow throughout the body!
Hair and nails grow faster.
You may also have problems with indigestion and constipation due to the slowing of your intestinal activity and the pressure that your uterus exerts on the bladder by magnifying.
Despite all these little annoyances, you radiate, especially if you are part of these women who feel now the first movements of the baby.
Life grows in you!
The baby begins to accumulate fat under his skin.
His eyes look in front of him, they are no longer positioned on the sides of the face.
The skin is transparent and fine.
At this stage, its external genitalia are defined.
With the space in the uterus,
The baby moves more and you start to feel the first moves.
Some women may associate them with "bubbles" or "butterfly wings".
It is a small wonder of 17cm and 150gr which is now active in the womb of the mother!
Towards the end of the 4th month, he manages to suck his thumbs, swallow and blink.
A thin protective lanugo appears on the body and allows the body to maintain a suitable temperature as long as there is not enough grease.
The baby reacts to hearing stimuli!
You can now communicate with him!
His eyelids are always closed but they allow the light to pass.
His intestines begin their work,
And if it is a girl, her uterus and her fallopian tubes are now in place.
At seven months
Within the mother, the uterus now reaches almost her thorax.
She is easily out of breath for everyday acts that now seem more difficult.
The changes on his body are important, and small concerns like cramps, hemorrhoid problems, varicose veins may appear...
Certainly, to be pregnant, it is far from being at rest... even if all this will be attenuated after the birth.
Even if the movements are now limited, you can continue to do soft sport: swimming, walking...
Regarding the baby, it begins to feel cramped with a size of 40cm and more than a kilo and a half at the end of the seventh month.
Thus, it limits its movements.
He is now very attentive to your conversations and the music that you pass him.
His nails begin to form, very thin hair appears on his head and long hair on the body: he will lose them in the last two months.
His face looks more and more like the one he will have when he will be born!
Baby will take its position for its exit: headdown, towards the ground!
Landing on the head is our way of having our feet on Earth!
This position is not without consequence, you feel more and more its weight because its measurements have increased further...
At nine months: landing!
At nine months, it's the last straight line!
The mother's belly is then very prominent and the back is more and more arched.
The weight is increasingly difficult to bear on the legs and back.
The breasts are swollen and are actively preparing for breastfeeding.
The urges to urinate are frequent.
Contractions sometimes occur, especially in the evening.
They are not regular and are not painful.
It is a normal and natural phenomenon which contribute in particular to the maturation of the cervix, which will make it easier to dilate during the delivery.
Sleep is sometimes difficult because it is not easy to find an adequate position, making travel and gestures more laborious.
Fatigue is felt, and it's normal!
During this month, madam, your uterus and your baby go down a little lower in your abdomen, it prepares for the exit of the baby
This movement of descent immediately brings relief to you because the uterus rests less on the other organs: you breathe more and you eat more easily!
Baby is going to devote the last few weeks to gain weight and strength to prepare for the big day.
It loses its fluff and becomes pink and chubby!
His lungs are ready to function.
At the end of pregnancy, baby measures on average 50cm and weighs just over 3kg!
His fingers, his toes are totally finished.
His eyes are blue for now, although he may change in the coming months.
The end of pregnancy marks the beginning of a great adventure....
Relax ... full of genes ...
Who do you look like?
Do you have blue eyes or brown eyes?
The hair frizzy or smooth?
Your appearance is a combination of traits, which corresponds to the set of characteristics identifying you!
Children resemble their parents or grandparents.
So parents pass on their traits to their children!
The science that studies the transmission and the passage of its features is called genetics!
Recessive or Dominant?
The human body consists of billions of "cells" each with a nucleus.
This nucleus contains all of our genetic information.
It is contained in our chromosomes which contain our DNA.
The chromosomes are made up of DNA that carries the genes, about 25000.
The genetic information is distributed on the 46 chromosomes, 23 pairs.
For each pair there is a paternal chromosome and a maternal chromosome.
Thus, for the same pair, the two chromosomes will not be identical.
The first 22 pairs are called "autosomes".
The 23rd pair is the one that determines the sex of the person: these are the X and Y chromosomes.
Women have two X chromosomes, while men have an X chromosome and a Y chromosome.
The DNA that makes up our chromosomes carries the genes.
The genes are therefore also present in two copies: a maternal copy and a paternel copy.
The DNA molecule, also known as deoxyribonucleic acid, is found in all of our cells.
It is the "detailed plan" of our organism also called the genetic code: it contains all the information necessary for the development and functioning of the body.
The DNA consists of four complementary elements: nucleotides: adenine(A), Thymine(T), guanine(G) and cytosine(C).
The gene is a piece of this DNA that corresponds to a particular genetic information that codes for
A single protein.
It is therefore a very small portion of chromosome.
Since we possess every chromosome in double, each gene is also present in "duplicate form" in our cells.
These two copies of the same gene, called "alleles", are most often different:
One of paternal origin and one of maternal origin!
The stronger of the two genes is called the dominant gene, because it expresses the traits or characteristics of the child; The other gene is said to be "recessive".
The genes indicate to each cell its role in the organism.
According to the information, they synthesize proteins: it is the translation of the genetic code.
We produce tens of thousands of proteins.
Each protein has a different role to play.
For example, hemoglobin is the protein used to transport oxygen in the blood.
Actin and myosin are proteins used for muscle contraction.
Antibodies protect the body from foreign bodies.
Other proteins, intervene to define the color of the eyes or the shape of the face.
A genetic abnormality, mutation or chromosomal abnormality can disrupt the production of proteins.
It gives some sort of "bad orders" to manufacture them with the consequence: absence of manufacture, excess of manufacture or abnormal manufacture.
The protein can no longer play its role, which generates a genetic disease.
Nevertheless, a gene unnormal does not always lead to a disease, some manufacturing errors can go totally unnoticed or expressed only in terms of the environment!
Indeed, the environment plays a role in the expression of genes.
Thus, in some cases, the role of genes is critical in the risk of developing a genetic disease.
For others, the environmental factors(food, tobacco, lifestyle...) play a more or less important role, sometimes diminishing the weight of the share due to the geneticheritage!
