Cardiovascular system is an important component of any living organism. Blood transports oxygen to tissues, various nutrients and hormones, and the products of the exchange of these substances transfers to the allocation authorities for their excretion and neutralization. It is enriched with oxygen in the lungs, nutrients in the organs of the digestive system. In the liver and kidney, metabolic products are output and neutralized. These processes are carried out by constant blood circulation, which occurs with the help of greater and small circles of blood circulation.

General

Attempts to open the circulatory system were in different centuries, but truly understood the essence of the circulatory system, opened its circles and described the scheme of their structure English doctor William Garvey. He first proved that in the body of an animal the same amount of blood is constantly moving along a closed circle due to pressure, which is created by heart abbreviations. In 1628, Gaver released a book. In it, he outlined his teaching about circles of blood circulation, creating the prerequisites for further in-depth study of the anatomy of the cardiovascular system.

In newborn children, blood circulates on both circles, but while the fruit was in the womb, his blood circulation had its own characteristics and was called placental. This is due to the fact that during the development of the fetus in the womb and digestive system The fetus is not fully functional, and it receives all the necessary substances from the mother.

Building circles structure

The main component of blood circulation is the heart. Big and small circles of blood circulation are formed by the vessels from him and are closed circles. They consist of vessels of various structures and diameter.

According to the function of blood vessels, they are accepted for the following groups:

1. 1. Summer. They start and finish both circle of blood circulation. These include pulmonary trunk, aorta, hollow and pulmonary veins.
2. 2. Mains. They distribute blood throughout the body. These are large and medium sized supplied artery and veins.
3. 3. Organ. With their help ensures the metabolism between the blood and tissues of the body. This group includes intraganic veins and arteries, as well as a microcirculatory link (arterioles, venules, capillaries).

Small circle

It works to saturate blood oxygen, which occurs in the lungs. Therefore, this circle is also called pulmonary. He begins in the right ventricle, which passes all the venous blood entered into the right atrium.

The beginning is the pulmonary trunk, which, when approaching the easiest, branches on the right and left pulmonary arteries. They carry the lungs of venous blood to the alveolis, which giving carbon dioxide and obtaining oxygen in return, becomes arterial. Blood-saturated oxygen on the pulmonary veins (two on each side) enters the left atrium, where the small circle ends. Then blood flows into the left ventricle, where does the big circle of blood circulation originate.

Big circle

He originates in the left ventricle the largest vessel of the human body - aorta. It carries arterial blood containing substances and oxygen necessary for vital activity. The aorta branches his arteries going to all tissues and organs, which subsequently cross the arterioles and then in capillaries. Through the wall of the latter, the metabolism and gases between the fabrics and vessels occurs.

Having obtained the products of exchange and carbon dioxide, blood becomes venous and going to Vienuly and further in Vienna. All veins merge into two large vessels - lower and upper hollow veins, which are then falling into the right atrium.

Functioning and value

Blood circulation is carried out due to heart cuts, combined operation of its valves and pressure gradient in organ vessels. With this, the necessary sequence of blood flow in the body is set.

Due to the action of circles of blood circulation, the body continues to exist. The constant circulation of blood is important for life and performs the following functions:

• gas (delivery of oxygen to organs and tissues and a removal from them according to the venous part of carbon dioxide);
• transportation of nutrients and plastic substances (come to fabrics in arterial channel);
• delivery of metabolites (recycled substances) to the allocation bodies;
• transport of hormones from the place of their development to the target authorities;
• circulation of thermal energy;
• delivery of protective substances to the place of claim (to places of inflammation and other pathological processes).

The coordinated work of all the links of the cardiovascular system, as a result of which there is continuous blood flow between the heart and organs, allows the exchange of substances with the external environment and maintain the constancy of the inner medium for the full functioning of the body for a long time.

What is a small circle of blood circulation?

From the right ventricle, blood is injected into the lung capillaries. Here she "gives" carbon dioxide and "takes" oxygen, after which it comes back into the heart, namely to the left atrium.

Why do you need a small circle of blood circulation?

How does a small circle of blood circulation functions?

Heart valves:

Positive and negative pressure:

Alveolas are located on the branches of the bronchial tree (bronchiola).

How is the blood flow in a small circle of blood circulation?

What is a big circle of blood circulation?

Circulatory system: According to the arteries, the blood saturated with oxygen is taken out of the heart and enters the authorities; On veins, blood saturated with carbon dioxide returns to the heart.

100,000 km of blood vessels:

How does a large circle of blood circulation?

Where are the blood vessels?

The main blood vessels:

Portal vein:

Connections:

Aerial embolism:

ON A NOTE:

Circular circulation of man

Human circuit circuit

Human blood circulation - a closed vascular path, providing a continuous blood current, carrying oxygen and nutrition, carrying carbon dioxide and metabolic products. It consists of two consistently connected circles (loops), beginning with the ventricles of the heart and flowing into the atrium:

• big circle circulation Starts in the left ventricle and ends in the right atrium;
• small circle circulation Starts in the right ventricle and ends in the left atrium.

Big (system) circle of blood circulation

Structure

Functions

The main task of a small circle of gas exchange in lightweight alveols and heat transfer.

"Additional" circle circles

Big circle of blood circulation video.

Both hollow veins bring blood into the right atriumwhere the venous blood from the heart is also coming. So the circle of blood circulation is closed. This blood flow is divided into a small and large circle of blood circulation.

Small circle of blood circulation video

Small circle circulation (pulmonary) begins on the right ventricle of the heart with a pulmonary barrel, includes the branches of the pulmonary barrel to the capillary network of lungs and pulmonary veins flowing into the left atrium.

Big circle circulation (Body) begins from the left ventricle of the heart of the aorta, includes all its branches, a capillary network and veins of organs and tissues of the whole body and ends in the right atrium.
Consequently, blood circulation is performed on two circles related circles.

The pattern of blood flow in circles was opened in the 17th century. Since then, the doctrine of heart and vessels has undergone significant changes by receiving new data and numerous studies. Today, people are rarely found that they do not know that there are circles of blood circulation of the human body. However, not everyone has detailed information.

In this review, we will try to briefly, but it is possible to describe what kind of blood circulation, consider the main features and functions of the blood circulation from the fetus, as well as the reader will receive information that such a circle of Villisyev is. The data presented will allow everyone to understand how the body is arranged.

For additional questions that may arise as read, the competent experts of the portal will answer.

Consultations are held online free of charge.

In 1628, the doctor from England William Garel was made to discovery that blood moves along a circular path - a large circle of blood circulation and a small circle of blood circulation. The latter includes blood flow to a light respiratory system, and large circulating throughout the body. In view of this, the scientist Garvey is a pioneer and made a discovery of blood circulation. Of course, hypocrat, M. Malpigi, as well as other well-known scientists contributed their contribution. Thanks to their work, the foundation was laid, which was the beginning of further discoveries in this area.

general information

The human circulation system consists of: heart (4 cameras) and two circles of blood circulation.

• He has two atrium and two ventricles.
• A large circle of blood circulation begins from the ventricle of the left chamber, and the blood is called arterial. From this point, blood flow moves by arteries to each organ. During a journey through the body, the arteries are converted into capillaries, which forms the exchange of gas. Further, blood flow turns into venous. Then comes in the atrium of the right chamber, and ends in the ventricle.
• The small circle of blood circulation is formed in the ventricle of the right chamber and the arteries are easy. There, blood exchanges, giving gas and taking oxygen, it turns out on the veins in the atrium of the left chamber, and ends in the ventricle.

In Scheme No. 1, it shows how circulation circles operate.

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It is also necessary to pay attention to the authorities and clarify the basic concepts that are important in the functioning of the body.

The blood circulation organs are as follows:

• atrium;
• ventricles;
• aorta;
• capillaries, incl. pulmonary;
• vienna: hollow, pulmonary, blood;
• artery: Pulmonary, Crown, Blood;
• alveolus.

Circulatory system

In addition to the small and large way of circulating blood flow, there is an peripheral path.

Peripheral blood circulation is responsible for the continuous process of blood flow between the heart and vessels. The muscle of the body, shrinking and relaxing, moves blood in the body. Of course, the volume of the pumped volume, the structure of the blood and other nuances is important. The blood circulation system works at the expense of pressure and pulses created in the organ. The heart pulsates depends on the systolic state and its shift to the diastolic.

The vessels of a large circle of blood circulation are dealt with blood flow by organs and tissues.

• Artery, leaving the heart, carry blood circulation. Arterioles are performed similarly.
• Vienna, as well as Venules promote blood return to the heart.

The arteries are the tubes on which a large circle circulation is moving. They have a rather large diameter. Capable to withstand high pressure due to thickness and plasticity. Possess three shells: internal, medium and outdoor. Due to elasticity, they are independently regulated depending on the physiology and the anatomy of each body, its needs and temperature of the external environment.

The arteries system can be represented as a corrupt-shaped bundle, which become the farther from the heart, the less. As a result, they have the appearance of capillaries in the limbs. Their diameter is not greater than the hair, but combine their arterioles and venules. Capillaries have thin walls and have one epithelial layer. Here is the exchange of nutrients.

Therefore, the value of each element should not be underestimated. Violation of the functions of one, leads to diseases of the entire system. Therefore, in order to maintain the functionality of the body, a healthy lifestyle should be conducted.

Cardiac third circle

As we found out - a small circle of blood circulation and large, these are not all components of the cardiovascular system. There is also the third path for which the flow of blood flow occurs and it is called a heart circle of blood circulation.

This circle originates from the aorta, or rather from the point where it is divided into two crown artery. Blood on them penetrates through the layers of the organ, then in small wreaths passes into the bellows sinus, opening in the atrium cameras of the right department. And some of the veins are directed to the ventricle. The path of blood flow in the coronary arteries is called coronary blood circulation. In the aggregate, these circles are a system that produces blood supply and saturation of organ nutrients.

Coronary blood circulation has the following properties:

• blood circulation in reinforced mode;
• the supply occurs in the diastolic state of the ventricles;
• the arteries here are a bit, so the dysfunction of one generates diseases of myocardium;
• cNS excitability enhances blood flow.

Scheme No. 2 shows how the coronary blood circulation is functioning.

The blood circulation system includes a little-known circle of Villisyev. Its anatomy is such that it is represented in the form of a system of vessels, which are located at the base of the brain. Its value is difficult to overestimate, because Its main function is to compensate for the blood, which he gives over their other "pools". The vascular system of Willisye Circle is closed.

The normal development of the Willisye path is only 55%. A common pathology is aneurysm and underdevelopment of the arteries connecting it.

At the same time, underdevelopment does not affect the state of a person, provided that there are no violations in other basins. It can be detected during MRI. The aneurysm of the arteries of the Willisian circulation is carried out as a surgical intervention in the form of its dressing. If aneurysta revealed, the doctor prescribes conservative treatments.

The vascular system of Willisyeva is designed not only for the supply of blood flow of the brain, but also as compensation for thrombosis. In view of this, the treatment of the Villisian path is practically not carried out, because There is no dangerous meaning of health.

Blood supply to human fetus

The blood circulation of the fetus is the following system. Bleeding with a high content of carbon dioxide from the upper area is included in the atria right chamber on the hollow vein. Through the hole, the blood is penetrated into the ventricle, and then into the pulmonary trunk. Unlike the blood supply of a person, the small circle of blood circulation of the embryo is not in the light respiratory tract, but in the damage of the arteries, and only then in the aorta.

Scheme No. 3 shows how the flow of blood from the fetus occurs.

Features Features:

1. Blood moves due to the contractile function of the organ.
2. Starting from the 11th week, breathing affects blood supply.
3. The placenta is given great importance.
4. A small circle of the blood circulation of the fetus does not function.
5. Mixed blood flow comes into the bodies.
6. Identical pressure in arteries and aorta.

Summing up the article, it should be emphasized how many circles are involved in the supply of the whole organism. Information on how each of them operates, makes it possible to read the reader to independently understand the intricacies of the anatomy and the functionality of the human body. Do not forget that you can ask a question online and get an answer from competent specialists with medical education.

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Tests

27-01. In which heart chamber is conditionally begins a small circle of blood circulation?
A) in the right ventricle
B) in the left atrium
C) in the left ventricle
D) in the right of atrium

27-02. Which of the statements correctly describes the flow of blood in a small circulation of blood circulation?
A) begins in the right ventricle and ends in the right of atrium
B) begins in the left ventricle and ends in the right of atrium
C) begins in the right ventricle and ends in the left atrium
D) begins in the left ventricle and ends in the left atrium

27-03. What kind of heart of the heart is blood from the veins of a large circle of blood circulation?
A) left atrium
B) left ventricle
C) right atria
D) right ventricle

27-04. What letter in the picture is indicated by the camera of the heart in which the light circle of blood circulation ends?

27-05. The figure shows the heart and large blood vessels of a person. What letter on it is indicated by the bottom hollow vein?

27-06. What figures are the vessels for which venous blood flows?

A) 2,3
B) 3,4.
C) 1,2
D) 1,4.

27-07. Which of the statements correctly describes the flow of blood for a large circulation of blood circulation?
A) begins in the left ventricle and ends in the right of atrium
B) begins in the right ventricle and ends in the left atrium
C) begins in the left ventricle and ends in the left atrium
D) begins in the right ventricle and ends in the right of atrium

Circulation - This is the movement of blood along the vascular system, providing gas exchange between the body and the external environment, the metabolism between organs and tissues and humoral regulation Different features of the body.

Circulatory system Includes heart and - aorta, arteries, arterioles, capillaries, venules, veins and. Blood moves along vessels due to the reduction of the heart muscle.

The blood circulation is performed on a closed system consisting of small and large circles:

• A large circle of blood circulation provides all organs and tissues with blood with nutrients contained in it.
• Small, or pulmonary, circulation circle is designed to enrich blood oxygen.

Circular circle circles were first described by the English scientist William Garvet in 1628 in labor "Anatomical research on the movement of the heart and vessels".

Small circle circulation Begins from the right ventricle, with a reduction in which the venous blood enters the pulmonary barrel and, passing through the lungs, gives carbon dioxide and is saturated with oxygen. Oxygen-enriched blood from the lungs by the pulmonary veins enters the left atrium, where the small circle ends.

Big circle circulation Begins from the left ventricle, with a reduction in which the blood enriched with oxygen is inserted into the aorta, arteries, arterioles and capillaries of all organs and tissues, and from there on venue and veins flow into the right atrium, where the big circle ends.

The largest vessel of a large circle of blood circulation is aorta that comes out of the left ventricle of the heart. Aorta forms an arc, from which arteries that carry blood to the head () and to the upper limbs (vertebral artery) are bred. Aorta passes down along the spine, where branches carrying blood to the abdominal organs, to the muscles of the body and lower limbs.

Arterial blood rich in oxygen is held throughout the body, delivering nutrients and oxygen to the tissues and oxygen necessary for their activities, and in the capillary system turns into venous blood. Deoxygenated bloodSounded by carbon dioxide and cellular exchange products returns to the heart and comes from it to the lungs for gas exchange. The largest veins of a large circle of blood circulation are the upper and lower hollow veins flowing into the right atrium.

Fig. Scheme of small and large circles of blood circulation

Attention should be paid to how the blood circulation systems of the liver and kidneys are included in a large circulation circle. All blood from the capillaries and veins of the stomach, the intestines, the pancreas and the spleen enters the portal vein and passes through the liver. In the liver, the portable vein branches into small veins and capillaries, which are then again connected to the common trunk of the hepatic vein flowing into the lower hollow vein. All the blood of the abdominal organs before entering a large circle of blood circulation flows through two capillary networks: the capillaries of these organs and the liver capillaries. The gorgeous liver system plays a big role. It provides neutralization poisonous substanceswhich are formed in the thick intestine when the uninoxotes are splitted in the small intestine and the colon mucosa into the blood is absorbed. The liver, like all other organs, also receives arterial blood through the hepatic artery extending from the abdominal artery.

There are two capillary networks in the kidneys: there is a capillary network in every Malpigiyev Glomechka, then these capillaries are connected to the arterial vessel, which again disintegrates the capillaries that have soaked the convolves.

Fig. Circulatory scheme

A feature of blood circulation in the liver and kidneys is the slowdown of the blood flow due to the function of these organs.

Table 1. Difference of blood current in large and small circles of blood circulation

Time of blood circuit - The time of a single passage of blood particle over the large and small circles of the vascular system. Read more next section of the article.

Patterns of blood flow by vessels

Basic principles of hemodynamics

Hemodynamics - This is a section of physiology that studies patterns and mechanisms of blood flow through the vessels of the human body. With its study, terminology is used and the laws of hydrodynamics are taken into account - the science of the movement of liquids.

The speed with which blood moves but vessels depends on two factors:

• from the difference in blood pressure at the beginning and end of the vessel;
• from resistance, which meets fluid on its path.

Pressure difference contributes to the movement of the fluid: what it is more, the more intense is the movement. Resistance in a vascular system that reduces blood flow rate depends on a number of factors:

• the length of the vessel and its radius (the larger length and less radius, the more resistance);
• blood viscosity (it is 5 times more water viscosity);
• friction of blood particles about the wall of the vessels and among themselves.

Hemodynamic indicators

The rate of blood flow in vessels is carried out according to the laws of hemodynamics, common with the laws of hydrodynamics. The rate of blood flow is characterized by three indicators: the volumetric rate of blood flow, the linear speed of blood flow and the time of blood circuit.

Surrounding speed of blood flow - The amount of blood flowing through the cross section of all vessels of this caliber per unit of time.

Linear blood flow rate - The speed of movement of a separate blood particle along the vessel per unit of time. In the center of the vessel, the linear speed is maximum, and near the vessel wall is minimal due to increased friction.

Time of blood circuit - The time during which the blood passes through the large and small circles of blood circulation. It is the norm of 17-25 p. About 1/5 is spent on the passage through a small circle, and on the passage through large - 4/5 of this time

Driving force of blood flow but the system of vessels of each of the circles of blood circulation is the difference in blood pressure ( ΔР.) In the initial section of the arterial channel (aorta for a large circle) and the final section of the venous bed (hollow veins and right atrium). Blood pressure difference ( ΔР.) At the beginning of the vessel ( P1) And at the end of it ( P2.) It is the driving force of blood stream through any vessel of the circulatory system. The strength of blood pressure gradient is spent on overcoming resistance to blood flow ( R.) In the system of vessels and in each separate vessel. The higher the blood pressure gradient in the circle of blood circulation or in a separate vessel, the greater the bulk blood flow.

The most important indicator of blood flow by vessels is Blood flow rate, or Volumetric blood flow(Q.), under which they understand the volume of blood flowing through the total cross section of the vascular bed or section of a separate vessel per unit of time. The volumetric rate of blood flow is expressed in liters per minute (l / min) or milliliters per minute (ml / min). To estimate the bulk blood flow through the aorta or the total cross section of any other level of blood circulation vessels use the concept Volumetric system blood flow. Since per unit of time (minute) through the aorta and other vessels of a large circle of blood circulation proceeds the entire amount of blood thrown by left ventricle during this time, synonymous with the concept of systemic volumetric blood flow is the concept (IOC). MOK adult man alone is 4-5 l / min.

There are also bulk blood flow in the organ. In this case, they mean the total blood flow, flowing per unit of time through all the brings arterial or submitting venous vessels of the organ.

Thus, bulk blood flow Q \u003d (P1 - P2) / R.

In this formula, the essence of the basic law of hemodynamics, claiming that the amount of blood flowing through the total cross section of the vascular system or a separate vessel per unit of time is directly proportional to the blood pressure difference at the beginning and at the end of the vascular system (or vessel) and inversely proportional to the current resistance blood.

The total (systemic) minute blood flow in a large circle is calculated taking into account the magnitudes of the average hydrodynamic blood pressure at the beginning of the aorta P1, and at the mouth of hollow veins P2. Since the blood pressure is close to 0 then in the expression for calculating Q. or IOC is substituted Requal to the average hydrodynamic arterial blood pressure at the beginning of the aorta: Q. (IOC) = P./ R..

One of the consequences of the basic law of hemodynamics is the driving force of the blood current in the vascular system - due to blood pressure generated by the work of the heart. Confirmation of the decisive value of blood pressure for blood flow is the pulsating nature of the blood current throughout the cardiac cycle. During the systole of the heart, when blood pressure reaches the maximum level, the bloodstream increases, and during diastole, when blood pressure is minimal, the blood flow is weakened.

As the blood progresses along the vessels from the aorta to the veins, the blood pressure decreases and the rate of its decrease is proportional to the resistance of blood flow in the vessels. The pressure in the arteriols and capillaries is particularly quickly reduced, as they have a large blood flow resistance, having a small radius, greater total length and numerous branches that create an additional obstacle to blood flow.

Resistance to blood flow, created in the entire vascular bed of a large circle of blood circulation, called Common peripheral resistance (OPS). Consequently, in the formula for calculating the volume blood flow symbol R. It is possible to replace it with analogue - OPS:

Q \u003d P / OPS.

From this expression, a number of important consequences are derived to understand the processes of blood circulation in the body, assess the results of measuring blood pressure and its deviations. The factors affecting the resistance of the vessel for the fluid current are described by the Poiseil law, according to which

where R. - resistance; L. - length of the vessel; η - blood viscosity; Π - number 3.14; r. - Vessel radius.

From the above expression implies that since the numbers 8 and Π are constant L. In an adult, a little changes, the magnitude of the peripheral resistance of blood flow is determined by the changing values \u200b\u200bof the radius of the vessels r. and blood viscosity η ).

It has already been mentioned that the radius of the muscular type vessels can quickly change and have a significant effect on the amount of resistance to blood flow (hence their name is resistive vessels) and the value of blood flow through organs and tissues. Since resistance depends on the size of the radius in the 4th degree, even small fluctuations in the radius of the vessels strongly affect the values \u200b\u200bof blood flow and blood flow. So, for example, if the radius of the vessel decreases from 2 to 1 mm, then it will increase by 16 times and with a constant pressure gradient of blood flow in this vessel will also decrease 16 times. Reverse resistance changes will be observed by increasing the radius of the vessel 2 times. With a constant average hemodynamic pressure of blood flow in one body, it may increase in the other, depending on the reduction or relaxation of the smooth muscles of bringing arterial vessels and veins of this body.

Blood viscosity depends on the blood content of erythrocytes (hematocrit), protein, blood plasma lipoproteins, as well as from the aggregate state of the blood. Under normal conditions, blood viscosity does not change so quickly as the lumen of the vessels. After blood loss, with erythrogenation, hypoproteinemia blood viscosity decreases. With significant erythrocytosis, leukemia, increased aggregation of red blood cells and hypercoagulation, blood viscosity is capable of significantly increasing, which entails the increase in resistance to blood flow, an increase in the load on myocardium and may be accompanied by a bleeding violation in the microcirculatory vessels.

In the established blood circulation mode, the blood volume, exiled to the left ventricle and flowing through the cross section of the aorta is equal to the volume of blood flowing through the total cross-section of the vessels of any other section of a large circle of blood circulation. This blood volume returns to the right atrium and enters the right ventricle. From it, blood is expelled in a small circle of blood circulation and then through the pulmonary veins returns to left heart. Since the IOC of the left and right ventricles is the same, and large and small circulation circles are connected in series, then the volumetric rate of blood flow in the vascular system remains the same.

However, during the change of blood flow conditions, for example, when moving from horizontal to a vertical position, when the strength of gravity causes a temporary accumulation of blood in the veins of the bottom of the body and the legs, for a short time, the IOC left and right ventricles can become different. Soon the intracardiac and extracardial mechanisms of the regulation of the heart level the volume of blood flow through a small and large circulation circle.

With a sharp decrease in the venous blood return to the heart, which causes a decrease in the shock volume, blood pressure can be reduced. With a pronounced reduction, blood flow to the brain can decrease. This explains the feeling of dizziness, which may occur with a sharp transition of a person from horizontal in vertical position.

Volume and linear speed of blood currents in vessels

The total blood volume in the vascular system is an important homeostatic indicator. The average value of it is 6-7% for women, for men 7-8% of the body weight and is in the range of 4-6 liters; 80-85% of blood from this volume - in the vessels of a large circle of blood circulation, about 10% - in the vessels of a small circle of blood circulation and about 7% - in the cavities of the heart.

The most blood is contained in the veins (about 75%) - this indicates their role in the deposition of blood both in large and in a small circulation of blood circulation.

Blood flow in vessels is characterized not only by volume, but also linear speed of blood flow. Under it understand the distance to which the blood particle moves per unit of time.

There is a relationship between the bulk and linear blood flow rate described by the following expression:

V \u003d Q / PR 2

where V.- linear speed of blood flow, mm / s, cm / s; Q.- The volumetric speed of blood flow; P - a number equal to 3.14; r. - Vessel radius. Value PR 2. Reflects the cross-sectional area of \u200b\u200bthe vessel.

Fig. 1. Changes in blood pressure, linear blood flow velocity and cross-sectional area in various sections of the vascular system

Fig. 2. Hydrodynamic characteristics of the vascular bed

From the expression of the dependence of the magnitude of the linear velocity from the volumetric system in the vessels of the circulatory system, it can be seen that the linear speed of blood flow (Fig. 1.) is proportional to the volumetric blood flow through the vessel (s) and inversely proportional to the cross-sectional area of \u200b\u200bthis vessel (s). For example, in aorta having the smallest cross-sectional area in a large circulation circle (3-4 cm 2), the linear speed of blood The greatest and is at rest about 20-30 cm / s. With exercise, it may increase 4-5 times.

In the direction of the capillars, the total transverse lumen of the vessels increases and, therefore, the linear rate of blood flow in the arteries and arteriols is reduced. In capillary vessels, the total cross-sectional area of \u200b\u200bwhich is greater than in any other separation of the large circle vessels (500-600 times the cross section of the aorta), the linear blood flow rate becomes minimal (less than 1 mm / s). Slow blood flow in capillaries creates the best conditions for the flow exchange processes Between blood and tissues. In veins, the linear rate of blood flow increases due to the decrease in the area of \u200b\u200btheir total cross-section as it approaches the heart. At the mouth of the hollow veins, it is 10-20 cm / s, and with loads increase to 50 cm / s.

The linear speed of the plasma movement and depends not only on the type of vessel, but also from their location in the blood flow. The laminar type of blood flow is distinguished, in which the blood notch can be divided into layers. In this case, the linear speed of the flow of blood layers (mainly plasma), close or adjacent to the vessel wall, is the smallest, and the layers in the center of the flow is the largest. Between the endothelium of blood vessels and the closed blood layers, friction forces arise, creating shear stresses on the endothelium. These stresses play a role in the development of the endothelium of vascular factors governing the clearance of vessels and the rate of blood flow.

Erythrocytes in vessels (with the exception of capillaries) are located mainly in the central part of the blood flow and move in it with a relatively high speed. Leukocytes, on the contrary, are located preferably in the interface layers of blood flow and perform rolled movements at low speed. This allows them to bind to adhesion receptors in places of mechanical or inflammatory damage to the endothelium, stick to the vessel wall and migrate to the tissue to perform protective functions.

With a significant increase in the linear velocity of blood flow in the narrowed part of the vessels, in places of departing from the vessel of its branches, the laminar nature of blood flow can be replaced by turbulent. At the same time, in the blood stream, the layering of the movement of its particles may be disturbed, large friction and shear stresses may occur between the vessel wall and blood than when laminar motion. The vortex blood flows are developing, the likelihood of damage to the endothelium and sediments of cholesterol and other substances in the interface of the vessel wall is developed. This is able to lead to a mechanical impairment of the structure of the vascular wall and initiating the development of trombic thromboms.

Time of complete blood circulation, i.e. The return of the blood particle into the left ventricle after its release and passing through the large and small circles circulation, is in the radiation of 20-25 s, or approximately after 27 stitties of the heart of the heart. Approximately a quarter of this time is spent on the movement of blood along the vessels of a small circle and three quarters - according to the vessels of a large circle of blood circulation.

/ 22.12.2017

What is a big circle. Small circle of blood circulation.

The pattern of blood flow through circles of blood circulation was opened by Gorel (1628). Subsequently, the doctrine of physiology and anatomy of blood vessels has been enriched with numerous data, discontinued mechanism of general and regional blood supply to organs.

Lovely animals and a person who have a four-chamber heart differ large, small and heart circles of blood circulation (Fig. 367). The central place in blood circulation is the heart.

367. Blood circulation scheme (forms, stenagota).

1 - general carotid artery;
2 - arc aorta;
3 - pulmonary artery;
4 - pulmonary vein;
5 - left ventricle;
6 - right ventricle;
7 - the crank barrel;
8 - upper mesenteric artery;
9 - Lower mesenteric artery;
10 - bottom hollow vein;
11 - aorta;
12 - general iliac artery;
13 - general iliac vein;
14 - femoral vein. 15 - Mortal Vienna;
16 - hepatic veins;
17 - connected Vienna;
18 - the upper hollow vein;
19 - internal jugular vein.

Small circle circulation (pulmonary)

Venous blood from the right atrium through the right atrial and stomach hole goes into the right ventricle, which, shrinking, pushes blood into the pulmonary trunk. It is divided into right and left pulmonary arteries penetrating into the lungs. In the pulmonary fabric, pulmonary arteries are divided into capillaries surrounding each Alveola. After the liberation of carbon dioxide and enrich them with oxygen, venous blood turns into arterial. Arterial blood in four pulmonary veins (in every light two veins) flows into the left atrium, then through the left atrocarditory hole goes into the left ventricle. From the left ventricle begins a large circle of blood circulation.

Big circle circulation

Arterial blood from the left ventricle during its reduction is thrown into the aorta. Aorta disintegrates the arteries supplying the blood limbs, torso,. All internal organs and ending with capillaries. From the blood of capillaries in the tissue, nutrients, water, salt and oxygen are extended, the products of exchange and carbon dioxide are resorvated. The capillaries are collected in Vienuly, where the venous vessel system begins, representing the roots of the upper and lower hollow veins. Venous blood on these veins enters the right atrium, where a large circle of blood circulation ends.

Cardiac circle of blood circulation

This circle of blood circulation begins from the aorta by two coronary hearth arteries, according to which the blood enters all layers and parts of the heart, and then assembled in small veins into the venous spray sinus. This vessel is widely opened in the right, atrium. Part of the small veins of the heart wall directly opens into the cavity of the right atrium and the ventricle of the heart.

A heartit is a central blood circulation body. It is a hollow muscle body consisting of two half: left-arterial and right - venous. Each half consists of reporting at the SERID and the ventricle of the heart.
The central organ of blood circulation is a heart. It is a hollow muscle body consisting of two half: left-arterial and right - venous. Each half consists of reporting at the SERID and the ventricle of the heart.

The venous blood on the veins enters the right atrium and further into the right ventricle of the heart, from the last to the pulmonary barrel, from where the pulmonary arteries should be in the right and left light. Here, the branches of the pulmonary arteries are branched to the smallest vessels - capillaries.

In the lungs, venous blood is saturated with oxygen, it becomes arterial and on the four pulmonary veins is heading to the left atrium, then enters the left ventricle of the heart. From the left ventricle of the heart, the blood enters the largest arterial highway - aorta and on its branches decaying in the tissues of the body to capillaries, is distributed throughout the body. Giving oxygen to the tissues and taking carbon dioxide from them, blood becomes venous. The capillaries, again connecting between themselves, form a vein.

All veins of bodies are connected in two large trunks - the upper vein and the lower hollow vein. IN upper vena hollow Blood is assembled from the regions and organs of the head and neck, the upper limbs and some parts of the walls of the body. The lower hollow vein is filled with blood from the lower extremities, walls and organs of the pelvic and abdominal cavities.

Big circle of blood circulation video.

Both hollow veins bring blood into the right atriumwhere the venous blood from the heart is also coming. So the circle of blood circulation is closed. This blood flow is divided into a small and large circle of blood circulation.

Small circle of blood circulation video

Small circle circulation (pulmonary) begins on the right ventricle of the heart with a pulmonary barrel, includes the branches of the pulmonary barrel to the capillary network of lungs and pulmonary veins flowing into the left atrium.

Big circle circulation (Body) begins from the left ventricle of the heart of the aorta, includes all its branches, a capillary network and veins of organs and tissues of the whole body and ends in the right atrium.
Consequently, blood circulation is performed on two circles related circles.

The cardiovascular system includes two systems: a blood circulation (blood circulation system) and a lymphatic (lymphorage system). The blood system combines the heart and vessels - tubular organs in which the blood circulates throughout the body. The lymphatic system includes branched in organs and tissues lymphatic capillaries, lymphatic vessels, lymphatic trunks and lymphatic ducts, for which Lymph flows towards large venous vessels.

Along the way of the lymphatic vessels from organs and parts of the body, numerous lymph nodes relating to organs lie to the stems and ducts immune system. The doctrine of the cardiovascular system is called angiocardium. The blood system is one of the main systems of the body. It provides delivery of nutrient tissues, regulatory, protective substances, oxygen, exchanging products, heat exchange. It is a closed vascular network that permeates all organs and fabrics, and having a centrally located pumping device - the heart.

The circulatory system is associated with numerous neurogucmoral connections with the activities of other organism systems, serves as an important link of homeostasis and provides blood supply to the current local needs adequate local needs. For the first time, an accurate description of the mechanism of blood circulation and the heart value is given by the founder of experimental physiology by an English physician W. Gorem (1578-1657). In 1628, he published a well-known work "anatomical study on the movement of the heart and blood in animals", in which he crossed the proof of blood movement along the vessels of a large circle circle.

The founder of the scientific anatomy A. Vesaly (1514-1564) in its work "On the structure of the human body" gave the correct description of the structure of the heart. The Spanish doctor M. Server (1509-1553) in the book "Restoration of Christianity" correctly presented a small circle of blood circulation correctly, describing the path of blood flow from the right ventricle to the left atrium.

Blood vessels of the body are combined into a large and small circles of blood circulation. In addition, an embossing circle of blood circulation is additionally isolated.

1) Big circle circulation - bodily , starts from the left ventricle of the heart. It includes aorta, arteries of different caliber, arterioles, capillaries, venules and veins. A large circle ends with two hollow veins falling into the right atrium. Through the walls of the capillaries of the body, the metabolism between blood and tissues. Arterial blood gives oxygen tissues and, saturated with carbon dioxide, turns into venous. Usually, a vessel of the arterial type (arteriol) is suitable for the capillary network, and Veneula leaves it.

For some organs (kidney, liver) there is a retreat from this rule. So, an artery is suitable for the ball of renal calf - bringing a vessel. It comes out of the glider, the artery is also a vessel. The capillary network inserted between the two same type vessels (arteries) is called arterial wonderful network. By type of the wonderful network, a capillary network is built between bringing (interdolkaya) and enduring (central) veins in the liver luxury - venous wonderful network.

2) Small circle circulation - pulmonary , starts from the right ventricle. It includes a pulmonary trunk, branching into two pulmonary arteries, smaller arteries, arterioles, capillaries, venules and veins. Ends in four pulmonary veins falling into the left atrium. In the capillaries of the lungs, the venous blood enriched with oxygen and freeing from carbon dioxide, turns into arterial.

3) Vented circle of blood circulation - cordial , Includes the heart vessels for the blood supply to the heart muscle. It begins with the left and right coronary arteries, which are departed from the initial department of the aorta - the bulbs of aorta. Packed by capillars, blood gives oxygen and nutrients into the heart muscle, receives the exchange products, including carbon dioxide, and turns into venous. Almost all veins of hearts fall into a common venous vessel - a bellows sinus, which opens into the right atrium.

Only a small amount of so-called the smallest veins of the heart falls on their own, bypassing the spray sinus, in all heart cameras. It should be noted that the heart muscle needs the permanent delivery of a large amount of oxygen and nutrients, which is ensured by the rich blood supply to the heart. With the mass of the heart, which is only 1 / 125-1 / 250 on the body weight, 5-10% of the whole blood emitted into the aorta comes into the coronary artery.

In the human body, blood moves two closed vessel systems connected with a heart, - small and big circles of blood circulation.

Small circle circulation - This is the path of blood from the right of gastroincing to the left atrium.

Venous, with low oxygen content of blood gets into the right side of the heart. Reducing right ventriclethrows it in easy artery.. In two branches, which are divided by light artery, this blood flows to light. There, the branches of the light artery, divided into all the smallest arteries, go to capillarieswhich dense numerous lung bubbles containing air. Passing on capillaries, blood is enriched with oxygen. At the same time, carbon dioxide from the blood goes into the air, which fills the lungs. Thus, in the capillaries of lungs, venous blood turns into artery-alnya. It falls into the veins, which, connecting with each other, form something light veinswho fall into left atrium(Fig. 57, 58).

Time of blood cycle in a small circle of blood circulation - 7-11 seconds.

Big circle circulation - This is the path of blood from le-voischka through arteries, capillaries and veins to the right atrium. Material from site.

Left ventricle, shrinking, pushes arterial blood in aORTU - The biggest artery of a person. Arteries that give blood to all organs, in particular in the heart, are born. The arteries in each body are gradually branched, forming dense grids of smaller arteries and capillaries. From the capillaries of a large circle of blood circulation to all body tissues come with oxygen and nutritional substances, and carbon dioxide gas passes from cells into capillaries. In this case, blood turns from arterial to venous. The capillaries merge into veins, sleep-challers in small and then into larger. Of these, all the blood is going to two large hollow Vienna. Upper Vienna carries blood from the head, neck, hands, and lower hollow vein - from all other parts of the body. Both hollow veins flow into the right atrium (Fig. 57, 58).

The time of blood cycle in a large circulation circle is 20-25 seconds.

Venous blood from the right atrium enters the right ventricle, from which flows in a small circulation of blood circulation. When leaving the aortic and light artery from the ventricles of the heart are placed alley valves (Fig. 58). They have the form of pockets placed on the inner walls of blood co-ships. When the blood is pushed into the aorta and the light artery, the semi-lunged clay pan is pressed against the walls of the vessels. When the ventricles relax, the blood can not return to the heart due to the fact that, crouching into pockets, it is stretching them and they are tightly closed. Consequently, the semi-lunut valves provide blood movement in one direction - from the ventricles in the artery.

On this page, material on the themes:

• Circles of blood circulation Summary of lectures

• Report on the system of human circulatory system

• Lectures circle circulation Animal scheme

• Big and Small Crucifier Crucifier Cheat Sheet

• The advantage of two circles of blood circulation compared to one

Questions about this material:

Big and small circulation circulation were opened by Gorel in 1628. Later, scientists of many countries made important discoveries concerning anatomical structure and the functioning of the circulatory system. To this day, medicine moves forward, studying methods for treating and restoring vessels. Anatomy is enriched with new data. They reveal the mechanisms of general and regional blood supply to tissues and organs. A person has a four-chamber heart that makes blood circulate over the large and small circles of blood circulation. This process is continuous, thanks to it absolutely all organism cells receive oxygen and important nutrients.

The value of blood

Big and small circles of blood circulation deliver blood to all tissues, thanks to which our body is working properly. Blood is a binding element that provides the vital activity of each cell and each organ. Oxygen and nutritional components are coming to the tissues, including enzymes and hormones, and metabolic products are output from the intercellular space. In addition, it is blood that provides a constant temperature of the human body, protecting the body from pathogenic microbes.

Nutrients are continuously income from the digestive organs in the blood plasma and spread to all tissues. Despite the fact that a person constantly uses food containing a large number of salts and water, the constant balance of mineral compounds is maintained in the blood. This is achieved by removing excess salts through the kidneys, light and sweat glands.

A heart

A large and small circles of blood circulation are departed from the heart. This hollow organ consists of two atrial and ventricles. The heart is located on the left in the chest area. His weight in an adult, on average, is 300 g. This body is responsible for pumping blood. In the work of the heart, three main phases are distinguished. Reducing the atria, ventricles and pause between them. It takes less than one second. One minute, the human heart is reduced at least 70 times. Blood moves along the vessels with a continuous flow, constantly flows through the heart from a small circle in large, carrying out oxygen to organs and tissues and bringing carbon dioxide into alveios.

Systemic (big) circle of blood circulation

And the large, and small circles of blood circulation perform the function of gas exchange in the body. When blood returns from the lungs, it is already enriched with oxygen. Next, it must be delivered to all tissues and organs. It is this function that performs a large circle of blood circulation. He takes its beginning in the left ventricle, taking blood vessels to the tissues, which branched to small capillaries and gas exchange. The system circle ends in the right atrium.

Anatomical structure of a large circle of blood circulation

A large circle of blood circulation originates in the left ventricle. It goes into large arteries saturated with oxygen blood. Finding into the aorta and shoulder barrel, it rushes to the tissues at a huge speed. On one large artery in the upper part of the body, and on the second - to the bottom.

The shoulder barrel is a large artery separated from aorta. On it rich in oxygen blood is coming up to the head and hands. The second large artery - aorta - delivers blood into the lower body, to the legs and tissues of the body. The two of these major blood vessels, as already mentioned above, are repeatedly divided into smaller capillaries, which the messengers permeate organs and tissues. These smallest vessels deliver oxygen and nutrients into the intercellular space. Carbon dioxide and other the necessary organism Metabolism products. On the way back to the heart, the capillaries are again connected into larger vessels - veins. Blood in them flows slower and has a dark shade. Ultimately, all vessels running from the bottom of the body are combined into the lower hollow vein. And those that go from the upper part of the body and the head - in the upper hollow vein. Both of these vessels fall into the right atrium.

Small (pulmonary) circle circulation

A small circle of blood circulation originates in the right ventricle. Further, making a complete turn, the blood goes into the left atrium. The main function of the small circle is gas exchange. Carbon dioxide is derived from the blood, which saturates the organism with oxygen. The gas exchange process is carried out in the lung alveoli. Small and large circulation circles perform several functions, but their basic value is to conduct blood throughout the body, covering all organs and tissues, while maintaining heat exchange and metabolic processes.

Anatomical device of a small circle

From the right ventricle of the heart comes out venous, poor blood oxygen content. It enters the largest small circle artery - pulmonary trunk. It is divided into two separate vessels (right and left artery). This is a very important feature of a small circle of blood circulation. Right artery brings blood to the right light, and left, respectively, to the left. Approaching the main body of the respiratory system, the vessels begin to share to smaller. They branched until they reach the size of thin capillaries. They cover everything easy, increasing in thousands of times the area at which gas exchange occurs.

A blood vessel is suitable for each smallest alveolu. From atmospheric air, blood separates only the finest wall of the capillary and lung. It is so gentle and porous that oxygen and other gases can freely circulate through this wall in the vessels and alveoli. Thus, gas exchange is carried out. Gas moves on the principle of greater concentration to the smaller. For example, if there are very little oxygen in dark venous blood, it begins to flow into capillaries from atmospheric air. But with carbon dioxide, on the contrary, it goes into the lung alveoli, since there is its concentration below. Next, the vessels are again combined into larger. Ultimately, there are only four large pulmonary veins. They carry the heart-enriched with oxygen bright red blood arterial blood, which flows into the left atrium.

Circulatory time

The period of time for which blood has time to go through a small and large circle, is called the time of complete blood circulation. This indicator is strictly individual, but on average it takes from 20 to 23 seconds at rest. With muscular activity, for example, during running or jumping, the rate of blood flow increases several times, then the full turnover of blood on both circles can be made in just 10 seconds, but such a pace cannot withstand the body for a long time.

Cardiac circle of blood circulation

Large and small circles of blood circulation provide gas exchange processes in the human body, but blood circulates in the heart, and in a rigid route. This path is called the "Heart Circle of Circulation". He begins with two large coronary heart arteries from the aorta. On them, the blood enters all parts and layers of the heart, and then in small veins going to the venous spray sinus. This large vessel opens into the right heart atrial atrium with its wide mouth. But some of the small veins directly goes into the cavity of the right ventricle and the atrium of the heart. This is how difficult it is the blood system of our body.

Circulation circles

Arterial and venous vessels are not isolated and independent, but are interconnected as a single system of blood vessels. The blood circulation circle forms two circles: big and small.

The flow of blood according to the vessels is possible due to the pressure difference at the beginning (artery) and the end (veins) of each circle circle, which creates the work of the heart. In the arteries, the pressure is higher than in the veins. With abbreviations (systole), the ventricle throws an average of 70-80 ml of blood each. Blood pressure rises and the walls are stretched. During the diastole (relaxation) of the walls return to the original position, pushing the blood further, providing its uniform current according to the vessels.

Speaking about circles of blood circulation, you must answer questions: (where? And what?). For example: where does it end?, Begins? - (in which ventricle or atrium).

What ends?, Begins? - (what vessels) ..

A small circle of blood circulation carries out blood delivery into the lungs where gas exchange occurs.

It begins in the right ventricle of the heart with a pulmonary barrel, in which the venous blood comes during the stomach systole. The pulmonary trunk is divided into the right and left pulmonary arteries. Each artery enters the light through his gate and, accompanying the structures of the "bronchial tree" reaches structurally - functional units of light - (AcNus) - sharing to the blood capillaries. There is gas exchange between blood and alveoli content. Venous vessels form in each light two pulmonary

vienna, which carry arterial blood to heart. A small circle of blood circulation in the left atrium is four pulmonary veins.

right ventricle hearts --- lightweight trunk --- light arteries ---

division of intra-high arteries --- arterioles --- blood capillaries ---

venules --- The fusion of intra-road veins - - --- left atrium.

what a vessel and in which heart chamber begins a small circle of blood circulation:

ventriculus Dexter.

truncus Pulmonalis

,toakim vessels begins and the small circle of blood circulationi.

begins from the right ventricle with a light barrel

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Vessels forming a small circle of blood circulation:

truncus Pulmonalis

what vessels and in which heart chamber the small circle of blood circulation ends:

Atrium sinistrum

A large circle of blood circulation delivers blood delivery to all body bodies.

From the left ventricular heart, arterial blood during systole is sent to the aorta. The arteries of elastic and muscle types are departed from the aortic, intraganic arteries, which are divided to arterioles and blood capillaries. Venus venous blood through the venos system, then the intragranny veins, the extra ordered veins form the upper, lower hollow veins. They are heading to the heart and flow into the right atrium.

sequentially it looks like this:

the left ventricle of the heart --- Aorta --- artery (elastic and muscular) ---

intraganic arteries --- arterioles --- Blood capillaries --- Venules ---

intorganized veins are ---- upper and lower hollow veins

in which camera heart begins Big circle circulation and how

vesseloh. .

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v. Cava Superior.

v. Cava Inferior.

what vessels and in which heart chamber are a large circle of blood circulation:

v. Cava Inferior.