What kind of blood does the umbilical vein bear fruit. Fetal circulation

Fetal circulation is vital. With it, the baby gets everything nutrients. Therefore, it is necessary to monitor the condition of the fetus and mother. For this, it is necessary to visit a qualified doctor as planned. He will talk about the features of blood circulation in the fetus and mother.

Often occur various problems with health. They can cause improper development fetus. Medical advice is essential to avoid negative consequences. After conception, another circle of blood flow is formed in the mother's body, on which the life of the unborn baby depends.

Features of the fetal circulation

The umbilical canal is the connection between the placenta and the fetus. It consists of 2 arteries and a vein. Blood from a vein fills an artery through umbilical ring. When the blood reaches the placenta, it is saturated with vital nutrients, oxygen, and then returned to the fetus.

This happens along the umbilical vein, which connects to the liver, and there it divides into two more branches. Such blood is called arterial.

One branch enters the region of the inferior vena cava. The second goes to the liver, and there it is divided into small capillaries. This is how blood enters the vena cava, where it mixes with what comes from the lower body. The entire flow moves to the right atrium. The lower opening, which is located in the vena cava, helps move blood to the left side of the heart.

It should be noted some features of the fetal circulation, in addition to those mentioned above:

The function that the lungs must perform belongs to the placenta.
The right atrium, ventricle, and pulmonary trunk fill with blood after it exits the superior vena cava.
When a child is not breathing, the small pulmonary arteries create opposition. At the same time, low pressure is observed in the aorta compared to the pulmonary trunk, from where it leaves.
Volume cardiac output is 220 ml/kg/min. This is blood from the left ventricle and ductus arteriosus.

The fetal circulation scheme provides for 65% return of blood flow to the placenta. And 35% remains in the organs and tissues of the unborn baby.

Features of fetal blood flow

According to medical data, fetal circulation is determined by characteristic features:

There is a connection between the two heart halves. They are associated with large vessels. There are two shunts. The first involves blood circulation with the help of oval window which is located between the atria. The second shunt is characterized by blood circulation through the arterial opening. It is located between the pulmonary artery and the aorta.
Due to one and the second shunt, the time of blood movement through big circle more than moving it in the pulmonary circulation.
Blood nourishes all the organs of the unborn baby, which are necessary for him to live. This is the brain, heart, liver. It exits the ascending aorta along an arc more oxygenated than bottom body.
The fetal circulation in the human fetus maintains almost the same level of pressure in the area of the artery and the aorta. As a rule, this is 70/45 mm Hg. Art.
At the same time, both ventricles are contracted, on the right and left sides.
Compared to total cardiac output, the right ventricle draws more blood flow in 2/3. This is despite the fact that the system maintains a large loading pressure.
The pressure in the right atrium is slightly higher than in the left.

In addition, the blood circulation of the placenta maintains a fast speed, low resistance.

Circulatory system disorders

A pregnant woman must be constantly monitored by a qualified doctor. This will allow early identification of possible pathological processes. They affect not only the mother's body, but also the development of the fetus.

The doctor carefully diagnoses an additional circle of blood circulation. Violation during pregnancy can lead to irreversible consequences and even fetal death.

Medicine provides for 3 forms of pathology that can disrupt the circulatory process:

Utero-placental.
Placental.
Fetoplacental.

The existing connection between fetus, mother, placenta is vital. The child must receive not only oxygen, but also necessary nutrition. Also, this system helps to remove products after metabolic processes.

The placenta protects the fetus from ingestion various viruses, bacteria, and pathogens. They can infect an undeveloped organism through maternal blood. Violation of blood flow will lead to the fact that pathological processes develop in the placenta.

Methods for diagnosing disorders

It helps to determine how serious problems there are with blood flow, what damage the fetus has. ultrasonography and dopplerometry. Modern technologies allow you to check various vessels not only the mother, but also the fetus.

There are certain features that speak of circulatory disorders. The doctor pays attention to them during research:

the placenta becomes thinner;
present infectious diseases;
state amniotic fluid, deviations from the norms (if any).

Using dopplerometry, the doctor can determine 3 stages of blood flow disorders:

On the first one, there are minor deviations. The blood flow of the uterus, fetus and placenta is preserved.
At the second stage of violations, all circles of blood circulation in the fetus are affected.
The third stage is considered critical.

The procedure can be performed by all pregnant women, regardless of the term.. This is especially true for women at risk, for whom the likelihood of developing serious problems. Additionally, along with dopplerometry, and laboratory research blood.

Consequences of impaired blood flow

The functional system "mother - placenta - fetus" is one. If violations occur, placental insufficiency is formed. The placenta is the main source of nutrition and oxygen for the baby. Moreover, it connects the two most important systems- mother and fetus.

The anatomy is such that any pathology leads to disturbances in the child's circulatory system.

Important! Inadequate blood circulation leads to malnutrition of the child.

To determine the degree of the problem allow the stage of violation of blood flow. The last, third stage speaks of critical condition provisions. When the doctor determines possible violations, he takes action, prescribes treatment or surgical intervention. According to medical data, 25% of pregnant women experience placental pathology.

The blood circulation of the fetus is arranged in such a way that the needs of its development are fully met. by the time the child is born undergoes certain changes. With the first breath, the newborn has a rush of blood to the lungs and appears ordinary type blood circulation, different from intrauterine.

The process of formation of the heart of the fetus begins in the second week of pregnancy, and its formation is completed in the second month of intrauterine development. In this period, it acquires all the features of a four-chambered heart. Together with the formation of the heart, the vascular system develops, the blood circulation of the fetus. He receives oxygen and nutrients from his mother. Therefore, there are certain features of the blood supply to the unborn child.

How does fetal circulation work?

Oxygenated blood flows from the placenta through the umbilical vein. At the same time, about half of the blood is discharged from the umbilical cord through venous network fetus. The blood shed will pass vascular system fetal liver and enters the inferior vena cava. The rest of the blood enters the liver through Then it rushes through the veins of the liver into the inferior vena cava.

As a result of such features of blood circulation, the blood in the inferior vena cava is mixed. The oxygen content in it is greater than in the blood returning from the atrium (right). This is very important aspect, since both blood flows in the right atrium are separated, which means that they have different paths.

The fetal blood supply due to the separation of blood flow directions has the following features: its brain and myocardium are supplied with blood from high content oxygen. And less oxygenated blood enters the placenta through the descending aorta and umbilical arteries for oxygen saturation.

Incoming in right atrium blood (more of it) from the inferior vena cava through the foramen ovale is sent to the left atrium. Oxygen-rich blood is shed due to the lower edge of the secondary septum. This septum is called the Eustachian valve. It is located above the opening leading to the right atrium from the inferior vena cava.

Further, the process of mixing the incoming blood with a small amount of insufficiently oxygenated blood, which is returned through the fetus to the left atrium, takes place. From the left atrium, blood moves to the left ventricle and then is ejected into the ascending aorta. And from the aorta blood flow, rich in oxygen, is distributed in three directions:

1. In for the implementation of myocardial perfusion. This is approximately 9% of the blood ejected from the left ventricle.

2. To the brain and upper divisions torso. The amount of such blood is about 62%. It enters through the carotid and subclavian arteries.

Thus, the blood circulation of the fetus occurs. Its correct intrauterine development depends on many factors: the heredity of the expectant mother, her lifestyle, nutrition, etc.

Fruit size

In parallel with the process, its size increases. It grows every hour, every day. Before reaching twenty-one weeks of pregnancy, the fetus is measured from the parietal part to the sacrum. After this period, measurements are taken from head to toe. Knowing the size of the fetus, a woman can monitor how timely it develops.

The development of the child depends, among other things, on the increase in the weight of the expectant mother. Therefore, it is necessary to strictly follow the diet recommended by the doctor. In addition, it is necessary to carry out a set of special exercise. Compliance with all the prescriptions of specialists by the expectant mother will help the fetus develop in accordance with the timing.

The mother's blood rich in nutrients and oxygen flows through the umbilical vein to the fetus. Having passed the umbilical ring, the umbilical vein gives off branches to the liver and portal vein and then, in the form of the so-called duct of Arantia, flows into the inferior vena cava, which carries venous blood from the lower half of the body. The hepatic branches pass through the liver, merge into larger venous trunks and, in the form of hepatic veins, flow into the inferior vena cava.

Thus, the arterial blood that enters the fetus from the umbilical vein mixes with the venous blood of the inferior vena cava and enters the right atrium, where the superior vena cava flows, carrying venous blood from the upper half of the body. Between the mouths of the superior and inferior vena cava there is a valve, due to which the mixed blood from the inferior vena cava is directed to the oval hole located in the septum between the atria, and through it into the left atrium, and from here into the left ventricle.

The blood of the superior vena cava from the right atrium enters the right ventricle and from there to the pulmonary artery, but due to the fact that the lungs and pulmonary vessels of the unbreathing fetus are in a collapsed state, the blood, bypassing the pulmonary circulation, through the ductus arteriosus, connecting the pulmonary artery and the aorta, enters directly into the aorta. Thus, blood enters the aorta in two ways: partly through the foramen ovale into the left atrium and left ventricle, and partly through the right ventricle and ductus arteriosus. Vessels departing from the aorta nourish all organs and tissues, and upper half body receives more oxygenated blood. After giving up oxygen and absorbing carbon dioxide, blood from the fetus flows through the umbilical arteries to the placenta ( rice. 1).

Fig 1. Scheme of blood circulation in the fetus: 1 - umbilical arteries; 2 - umbilical vein: 3 - duct of Arantia; 4 - aorta; 5 - lower vein; 6 - botallian duct; 7 - right atrium; 8 - left atrium; 9 - pulmonary artery: 10 - left ventricle; 11 - right ventricle; 12 - superior vena cava; 13 - blood flow through the foramen ovale.

So the main hallmark intrauterine blood circulation is the shutdown of the pulmonary circulation, since the lungs do not breathe, and the presence of germinal blood tracts - the foramen ovale, the batalla and the ducts of Arantia.

During childbirth, with uterine contractions, a partial separation of the placenta from the uterine wall begins, resulting in placental fetal circulation is violated. In the blood of the fetus, the amount of oxygen decreases and the content of carbon dioxide increases - the phase of oxygen starvation begins. At right course childbirth at the time of birth due to irritation respiratory center the baby's first breath occurs. For the occurrence of breathing, the reaction to a lower ambient temperature compared to intrauterine and to the touch of the hands on the body of the child is also important.

After the birth of a child, its direct connection with the mother's body ceases. For getting enough oxygen, the newborn must breathe vigorously. An indicator of the sufficiency of breathing is a loud cry, as it occurs with increased exhalation.

The absence of a loud cry indicates that the child's lungs are poorly expanded and his breathing is not deep. In such cases, through various skin irritations or artificial respiration a loud shout should be made. If the child breathes only 8-10 times per minute and does not scream, he should not be transferred to the nursery.

With the first breath of the child, the lungs expand, the pulmonary vessels expand. Due to the suction action of the lungs, blood from the right ventricle begins to flow into the lungs, bypassing the ductus arteriosus. Oxygenated blood flows from the lungs through the pulmonary vein to the left atrium and then to the left ventricle. The flow of blood from the right atrium to the left ceases - the foramen ovale gradually overgrows, the arantia and botallian ducts and the remains of the umbilical vessels, which gradually turn into connective tissue ligaments, become empty. With the birth of a child, the pulmonary circulation begins to function in him, extrauterine circulation is established ( rice. 2).

Rice. 2. Scheme of blood circulation in a newborn. 1 - umbilical arteries; 2 - umbilical vein; 3 - Arantia duct; 4 - aorta; 5 - inferior vena cava; 6 - botallian duct; 7 - right atrium; 8 - left atrium; 9 - pulmonary artery; 10 - left ventricle; 11 - right ventricle; 12 - superior vena cava

Circulation intrauterine fetus, the so-called placental, differs from postnatal circulation in that, firstly, the pulmonary (small) circulation in the fetus passes blood, but does not participate in the process of gas exchange, as it happens from the moment of birth; secondly, there is a message between the left and right atria; thirdly, there is an anastomosis between the pulmonary trunk and the aorta. As a result, the fetus feeds on mixed (arterial-venous) blood, which reaches certain organs with a greater or lesser content of arterial blood.

In the placenta, placenta, the umbilical vein begins with its roots, v. umbilicalis, through which arterial blood oxidized in the placenta is sent to the fetus. Following in the composition of the umbilical cord (umbilical cord), funiculus umbilicalis, to the fetus, the umbilical vein enters through the umbilical ring, anulus umbilicalis, into the abdominal cavity, goes to the liver, to sulcus v. umbilicalis (fissura ligamenti teretis), and enters the thickness of the liver. Here, in the parenchyma of the liver, the umbilical vein connects with the vessels of the liver and, under the name of the venous duct, ductus venosus, together with the hepatic veins brings blood to the inferior vena cava, v. cava inferior.

Blood through the inferior vena cava enters the right atrium, where its main mass, through the valve of the inferior vena cava, valvula venae cavae inferioris, mainly in the first half of pregnancy, passes through the foramen ovale, foramen ovale, interatrial septum into the left atrium. From here it follows to the left ventricle, and then to the aorta, along the branches of which it goes first of all to the heart (along coronary arteries), neck and head and upper limbs(along the brachiocephalic trunk, left common carotid and left subclavian arteries). In the right atrium, except for the inferior vena cava, v. cava inferior, brings venous blood superior vena cava, v. cava superior, and coronary sinus of the heart, sinus coronarius cordis. Venous blood entering the right atrium from the last two vessels is sent along with a small amount of mixed blood from the inferior vena cava to the right ventricle, and from there to the pulmonary trunk, truncus pulmonalis. Into the aortic arch, below the place where the left subclavian artery, flows into ductus arteriosus, ductus arteriosus, which connects the aorta to the pulmonary trunk and through which blood from the latter flows into the aorta.

From pulmonary trunk blood flows through pulmonary arteries into the lungs, and its excess through the arterial duct, ductus arteriosus, is sent to the descending aorta. Thus, below the confluence of the ductus arteriosus, the aorta contains mixed blood entering it from the left ventricle, rich arterial blood, and blood from the arterial duct with great content venous blood. Along the branches of the chest and abdominal aorta this mixed blood is sent to the walls and organs of the chest and abdominal cavities, pelvis and to lower limbs. Part of this blood follows two - right and left - umbilical arteries, aa .. umbilicales dextra et sinistra, which, located on both sides Bladder, come out of abdominal cavity through the umbilical ring and as part of the umbilical cord, funiculus umbilicalis, reach the placenta. In the placenta, the fetal blood receives nutrients, gives off carbon dioxide and, enriched with oxygen, is again directed through the umbilical vein to the fetus.

After birth, when the pulmonary circulation begins to function and the umbilical cord is tied up, the umbilical vein, venous and arterial ducts, and distal umbilical arteries gradually become empty; all these formations are obliterated and form ligaments. Umbilical vein, v. umbilicalis, forms a round ligament of the liver, lig. teres hepatis; venous duct, ductus venosus, -venous ligament, lig. venosum; arterial duct, ductus arteriosus, - arterial ligament, lig. arteriosum, and from both umbilical arteries, aa .. umbilicales, strands are formed, medial umbilical ligaments, lig. umbilicalia medialia, which are located along inner surface front abdominal wall. The oval hole, foramen ovale, also overgrows, which turns into an oval fossa, fossa ovalis, and the valve of the inferior vena cava, valvula v. cavae inferioris, which lost its functional value, forms a small fold stretched from the mouth of the inferior vena cava towards the oval fossa.