Blood in the human body circulates in a closed system. Main function biological fluid– providing cells with oxygen and nutrients and excretion carbon dioxide and products of exchange.
A little about the circulatory system
The human circulatory system has a complex structure, biological fluid circulates in the small and big circle blood circulation
The heart, which acts as a pump, consists of four sections - two ventricles and two atria (left and right). Vessels, blood bearers from the heart are called arteries, to the heart are called veins. The arterial one is enriched with oxygen, the venous one – with carbon dioxide.
Thanks to interventricular septum, venous blood, which is on the right side of the heart, does not mix with arterial blood, which is on the right side. Valves located between the ventricles and atria and between the ventricles and arteries prevent it from flowing in the opposite direction, that is, from the very major artery(aorta) into the ventricle, and from the ventricle into the atrium.
When the left ventricle, whose walls are thickest, contracts, it creates maximum pressure, oxygen-rich blood is pushed into the systemic circulation and distributed through the arteries throughout the body. In the capillary system, gases are exchanged: oxygen enters the tissue cells, carbon dioxide from the cells enters the bloodstream. Thus, the arterial becomes venous and flows through the veins into the right atrium, then into the right ventricle. This is a large circle of blood circulation.
Further venous pulmonary arteries enters the pulmonary capillaries, where it releases carbon dioxide into the air and is enriched with oxygen, again becoming arterial. Now it flows through the pulmonary veins into the left atrium, then into the left ventricle. This closes the pulmonary circulation.
Venous blood is located in the right side of the heart
Characteristics
Venous blood differs in a number of parameters, ranging from appearance and ending with the functions performed.
- Many people know what color it is. Due to its saturation with carbon dioxide, its color is dark, with a bluish tint.
- It is poor in oxygen and nutrients, but it contains a lot of metabolic products.
- Its viscosity is higher than that of oxygen-rich blood. This is explained by an increase in the size of red blood cells due to the entry of carbon dioxide into them.
- She has more high temperature and more low level pH.
- Blood flows through the veins slowly. This is due to the presence of valves in them, which slow down its speed.
- There are more veins in the human body than arteries, and venous blood overall accounts for approximately two-thirds of the total volume.
- Due to the location of the veins, it flows close to the surface.
Compound
Laboratory tests make it easy to distinguish venous blood from arterial blood by composition.
- In the venous oxygen tension is normally 38-42 mmHg (in the arterial - from 80 to 100).
- Carbon dioxide - about 60 mm Hg. Art. (in arterial – about 35).
- The pH level remains 7.35 (arterial - 7.4).
Functions
The veins carry the outflow of blood, which carries metabolic products and carbon dioxide. Nutrients enter it and are absorbed by the walls. digestive tract, and produced by glands internal secretion hormones.
Movement through the veins
During its movement, venous blood overcomes gravity and experiences hydrostatic pressure, therefore, if a vein is damaged, it calmly flows in a stream, and if an artery is damaged, it flows in full swing.
Its speed is much lower than that of the arterial one. The heart pumps out arterial blood at a pressure of 120 mmHg, and after it passes through the capillaries and becomes venous, the pressure gradually drops and reaches 10 mmHg. pillar
Why is material taken from a vein for analysis?
IN venous blood contains breakdown products formed during metabolism. During diseases, substances enter it, which are in in good condition there shouldn't be. Their presence allows one to suspect the development of pathological processes.
How to determine the type of bleeding
Visually, this is quite easy to do: the blood from the vein is dark, thicker and flows out in a stream, while the arterial blood is more liquid, has a bright scarlet hue and flows out like a fountain.
Venous bleeding is easier to stop; in some cases, if a blood clot forms, it may stop on its own. A pressure bandage placed below the wound is usually required. If a vein in the arm is damaged, it may be enough to raise the arm up.
As for arterial bleeding, it is very dangerous because it will not stop on its own, the blood loss is significant, and death can occur within an hour.
Conclusion
The circulatory system is closed, so the blood, as it moves, becomes either arterial or venous. Enriched with oxygen, when passing through the capillary system, it gives it to tissues, takes up decay products and carbon dioxide and thus becomes venous. After this, it rushes to the lungs, where it loses carbon dioxide and metabolic products and is enriched with oxygen and nutrients, again becoming arterial.
Blood moves continuously through the vessels of the human body. The heart, due to its structure, clearly divides it into arterial and venous. They should not be mixed normally. Sometimes there are difficult situations, for example, during bleeding or taking fluid from a vessel, in which it is necessary to accurately determine its type. This article will tell you how it differs from venous. And we should start with anatomy.
Structure of the circulatory system
The four-chamber structure of the heart helps to separate arterial and venous fluid. Thus, they do not mix, which is necessary for the adequate functioning of the body.
There are 2 circles of blood circulation: small and large. Thanks to the first, blood passes through the capillaries of the lungs, is enriched with oxygen in the alveoli, becoming arterial. Then it goes to the heart, which, with the help of the powerful walls of the left ventricle, pushes it into a large circle through the aorta.
After the body tissues have taken all the nutrients from the capillaries, the blood becomes venous and returns through the systemic vessels of the same name to the heart, which sends it through the pulmonary arteries to the small one to again saturate it with oxygen.
So what's the difference? arterial blood from venous? What are their features?
Arterial
First of all, this species differs from the other in composition. The main function of blood is to deliver oxygen to organs and tissues. The process occurs in capillaries - the smallest vessels. In exchange for oxygen, cells give off carbon dioxide.
In addition to the most important for all living things chemical element, such blood is rich in nutrients that are absorbed into gastrointestinal tract and enter the venous system. Further her path is blocked by the liver. All substances coming from the gastrointestinal tract must be filtered. Dangerous and poisonous remain there, and pure venous blood gets the right to pass through the lungs and be converted into arterial blood. It delivers nutrients to organ cells that need nutrition.
Another distinctive feature This type of blood serves as a color. It has a bright scarlet color. The reason is hemoglobin. It has different composition. So what is the difference between hemoglobin in arterial and venous blood? This is a special protein that can carry oxygen. The combination with it gives the liquid a bright scarlet color.
Another important sign of how arterial blood differs from venous blood is the nature of movement through the vessels. This directly depends on the force with which it is expelled from the heart into a large circle, as well as on the structure of the artery wall. They are strong and elastic. Therefore, in case of injury, the contents of the vessel are poured out in a strong pulsating stream.
It is very difficult to compress arteries using soft tissue. Therefore, to stop blood loss, there are points where the vessels are as close as possible to the bone structures. It is necessary to press the artery tightly against the bone structure located above the injury site, since the arteries carry blood from top to bottom. It must be remembered that most arteries are deep and require a lot of effort to compress them.
Venous
This species has a darker, deeper burgundy color with a slight bluish tint. Hemoglobin gives it this color. The arterial system gave maximum oxygen to the tissues of the body. But therefore, venous blood differs from arterial blood in the presence of another substance in hemoglobin - carbon dioxide. This is how carboxyhemoglobin is formed. It just colors the substance in a dark red hue.
After transfer nutrients tissues give up their metabolic products, which must be removed from the body. Such substances include uric acid and others. Because of them high content Compared to arterial blood, it is venous blood that is used in laboratory research for the qualitative determination of a particular indicator.
Venous blood differs from arterial blood in that if a vessel is damaged, it will flow more systematically. Stopping this type of bleeding is much easier, especially when superficial trauma. It is enough to apply a pressure bandage. This difference in movement through the vessels is explained by the structure of the vein wall. It is very pliable and easy to press against soft tissues, such as muscles.
Meaning
Due to their differences and opposing characteristics, arterial and venous blood ensure the internal constancy of the body - homeostasis. For full health, you need to keep yourself in good shape and maintain complete balance. Otherwise, if any deviations appear, the condition will be disrupted and the person will get sick.
How is arterial blood different from venous blood? After reading the article, such a question should not bother a person. Based on the knowledge gained, you can easily determine the type of bleeding and save more than one life.
Blood performs in the body main function– provides organs with tissues with oxygen and other nutrients.
It takes carbon dioxide and other decay products from the cells. Thanks to this, gas exchange occurs, and the human body functions normally.
There are three types of blood that constantly circulate throughout the body. These are arterial (A.K.), venous (V.C.) and capillary fluid.
What is arterial blood?
Most people think that arterial view flows through the arteries, and venous flows through the veins. This is an erroneous judgment. It is based on the fact that the name of blood is associated with the name of blood vessels.
The system through which the fluid circulates is closed: veins, arteries, capillaries. It consists of two circles: large and small. This contributes to the division into venous and arterial categories.
Arterial blood enriches cells with oxygen (O 2). It is also called oxygenated. This blood mass from the left ventricle of the heart is pushed into the aorta and flows through the arteries of the systemic circle.
Having saturated the cells and tissues with O 2, it becomes venous, entering the veins of the systemic circle. In the pulmonary circulation, the arterial mass moves through the veins.
Some arteries are located deep in the human body and cannot be seen. The other part is located close to the surface of the skin: the radial or carotid artery. In these places you can feel the pulse. Read from which side.
How is venous blood different from arterial blood?
The movement of this blood mass occurs in a completely different way. The pulmonary circulation begins from the right ventricle of the heart. From here, venous blood flows through the arteries to the lungs.
More information about venous blood -.
There it gives off carbon dioxide and is saturated with oxygen, turning into an arterial type. The pulmonary vein returns blood to the heart.
In the large circulatory system, arterial blood flows from the heart through the arteries. Then it turns into V.K., and through the veins it enters the right ventricle of the heart.
The venous system is more extensive than the arterial system. The vessels through which blood flows are also different. So the vein has thinner walls, and the blood mass in them is a little warmer.
Blood in the heart does not mix. Arterial fluid is always in the left ventricle, and venous fluid is always in the right.
Differences between the two types of blood
Venous blood is different from arterial blood. The difference lies in the chemical composition of the blood, shades, functions, etc.
- Arterial mass bright red. This is explained by the fact that it is saturated with hemoglobin, which has added O 2. For V.K. Characteristic is a dark burgundy color, sometimes with a bluish tint. This suggests that it contains a high percentage of carbon dioxide.
- According to biology studies, the chemical composition of A.K. rich in oxygen. Average percentage of O 2 content healthy person– over 80 mmhg. IN VK. the indicator drops sharply to 38 – 41 mmhg. The carbon dioxide indicator is different. In A.K. it is 35 - 45 units, and in V.K. the proportion of CO 2 ranges from 50 to 55 mmhg.
Not only oxygen, but also useful microelements enter the cells from the arteries. In the venous there is a large percentage of breakdown and metabolic products.
- The main function of A.K. – provide human organs with oxygen and useful substances. VC. necessary in order to deliver carbon dioxide to the lungs for further removal from the body and to eliminate other breakdown products.
In addition to CO 2 and metabolic elements, venous blood also contains useful substances that absorb digestive organs. The blood fluid also contains hormones secreted by the endocrine glands.
- Blood through the arteries big ring blood circulation and the small ring moves with at different speeds. A.K. ejected from the left ventricle into the aorta. It branches into arteries and more small vessels. Next, the blood mass enters the capillaries, feeding the entire periphery with O 2. VC. moves from the periphery to the heart muscle. The differences are in pressure. Thus, blood is ejected from the left ventricle under a pressure of 120 millimeters of mercury. Further, the pressure decreases, and in the capillaries it is about 10 units.
Blood fluid also moves slowly through the veins of the systemic circle, because where it flows, it has to overcome gravity and cope with the obstacle of the valves.
- In medicine, blood sampling for a detailed analysis is always taken from a vein. Sometimes from capillaries. Biological material, taken from a vein, helps determine the condition of the human body.
The difference between venous bleeding and arterial bleeding
It is not difficult to distinguish between types of bleeding; even people far from medicine can do this. If an artery is damaged, the blood is bright red.
It flows in a pulsating stream and flows out very quickly. Bleeding is difficult to stop. This is the main danger of arterial damage.
It will not stop without first aid:
- The affected limb should be elevated.
- Hold the damaged vessel a little above the wound with your finger and apply a medical tourniquet. But it cannot be worn for more than one hour. Before applying a tourniquet, wrap the skin with gauze or any cloth.
- The patient should be urgently taken to the hospital.
Arterial bleeding may be internal character. It is called closed form. In this case, a vessel inside the body is damaged, and the blood mass enters the abdominal cavity or spills between organs.
The patient suddenly becomes ill, the skin turns pale. A few moments later he begins to severe dizziness , and he loses consciousness. This indicates a lack of O 2. Help with internal bleeding
Only doctors in the hospital can.
When bleeding from a vein, fluid flows out in a slow stream. Color – dark burgundy. Bleeding from a vein can stop on its own. But it is recommended to bandage the wound with a sterile bandage.
There is arterial, venous and capillary blood in the body.
The first moves through the arteries of the large ring and the veins of the small circulatory system.
Venous blood flows through the veins of the greater ring and the pulmonary arteries of the lesser circle. A.K. saturates cells and organs with oxygen.
Taking carbon dioxide and decay elements from them, the blood turns into venous. It delivers metabolic products to the lungs for further elimination from the body.
Video: Differences between arteries and veins Constant movement of blood through a closed circuit cardiovascular system
, which ensures gas exchange in tissues and lungs, is called blood circulation. In addition to saturating organs with oxygen, as well as cleansing them of carbon dioxide, blood circulation is responsible for delivering all necessary substances to the cells. Everyone knows that blood can be venous and arterial. In this article you will learn through which vessels more dark blood
, find out what is included in this biological fluid. This system includes blood vessels , which penetrate all tissues of the body and the heart. The process of blood circulation begins in the tissues where metabolic processes
through the capillary walls. The blood, which has given up all its useful substances, flows first to right half
heart, and then into the pulmonary circulation. There, it, enriched with useful substances, moves to the left, and then spreads in a large circle.. It is endowed with four chambers - two atria and two ventricles. The atria are divided interatrial septum, and the ventricles - interventricular. The weight of a human “motor” is from 250-330 grams.
The color of the blood in the veins and the color of the blood moving through the arteries are slightly different. You will learn a little later about which vessels the darker blood moves through and why it differs in shade.
An artery is a vessel that carries biological fluid saturated with useful substances from the “motor” to the organs. The answer to a fairly frequently asked question: “What vessels carry venous blood?” simple Venous blood is transported exclusively by the pulmonary artery.
The arterial wall consists of several layers, these include:
- outer connective tissue membrane;
- medium (consisting of smooth muscles and elastic hairs);
- internal (consisting of connective tissue and endothelium).
Arteries divide into small vessels called arterioles. As for capillaries, they are the smallest vessels.
The vessel that carries carbon dioxide-enriched blood from tissues to the heart is called a vein. Exception in in this case pulmonary vein - since it carries arterial blood.
Dr. W. Harvey first wrote about blood circulation back in 1628. The circulation of biological fluid occurs through the pulmonary and systemic circulation.
The movement of biological fluid in the systemic circle begins from the left ventricle, thanks to high blood pressure, the blood spreads throughout the body, nourishes all organs with beneficial substances and takes away harmful ones. Next, the transformation of arterial blood into venous blood is noted. Final stage- return of blood to the right atrium.
As for the small circle, it begins from the right ventricle. First, the blood gives off carbon dioxide, receives oxygen, and then moves to the left atrium. Next, through the right ventricle, the flow of biological fluid into the systemic circle is noted.
The question of which vessels carry darker blood is quite common. Blood is red in color; it differs only in shades due to the amount of hemoglobin and oxygen enrichment.
Surely many remember from biology lessons that arterial blood has a scarlet tint, and venous blood has a dark red or burgundy tint. Veins located nearby skin, also appear red when blood circulates through them.
In addition, venous blood differs not only in color, but also in function. Now, knowing through which vessels darker blood moves, you know that its color is due to its enrichment in carbon dioxide. The blood in the veins has a burgundy tint.
It contains little oxygen, but at the same time it is rich in metabolic products. It is more viscous. This is due to an increase in the diameter of red blood cells due to the influx of carbon dioxide into them. In addition, the temperature of the venous blood is higher, and the pH is lower.
It circulates through the veins very slowly (due to the presence of valves in the veins that slow down the speed of its movement). Wen in human body compared to arteries, much larger.
What color is the blood in the veins and what functions does it perform?
Do you know what color the blood in the veins is? The shade of biological fluid determines the presence of hemoglobin in red blood cells (erythrocytes). The blood circulating through the arteries, as already mentioned, is scarlet.
This is due to the high concentration of hemoglobin (in humans) and hemocyanin (in arthropods and mollusks), enriched with various nutrients.
Venous blood has a dark red tint. This is due to oxidized and reduced hemoglobin.
At the very least, it is unreasonable to believe the theory according to which the biological fluid circulating through the vessels is bluish in color, and when injured and in contact with air due to chemical reaction immediately blushes. It is a myth.
Veins may only appear bluish, this is due to simple laws physicists. When light hits the body, the skin reflects some of all the waves and therefore looks light or dark (this depends on the concentration of the coloring pigment).
You know what color venous blood is, now let's talk about the composition. You can distinguish arterial blood from venous blood using laboratory research. Oxygen tension - 38-40 mmHg. (in venous), and in arterial blood - 90. The content of carbon dioxide in venous blood is 60 millimeters of mercury, and in arterial blood - about 30. The pH level in venous blood is 7.35, and in arterial blood - 7.4.
The outflow of blood, carrying away carbon dioxide and products formed during metabolism, is carried out through the veins. It is enriched with useful substances that are absorbed into the walls of the gastrointestinal tract and produced by vital substances.
Now you know what color the blood is in the veins, you are familiar with its composition and functions.
Blood flowing through the veins overcomes “difficulties” during movement, which include pressure and gravity. That is why, in case of damage, biological fluid flows in a slow stream. But if the arteries are injured, blood spurts out like a fountain.
The speed at which venous blood moves is much less than the speed at which arterial blood moves. The heart pushes blood out high pressure. After it passes through the capillaries and becomes venous, a decrease in pressure to ten millimeters of mercury is noted.
Why is venous blood darker than arterial blood, and how to determine the type of bleeding
You already know why venous blood is darker than arterial blood. Arterial blood is lighter and this is due to the presence of oxyhemoglobin in it. As for the venous, it is dark (due to the content of both oxidized and reduced hemoglobin).
You've probably noticed that blood is taken from a vein for testing, and you've probably wondered, “why from a vein?” This is due to the following. The composition of venous blood includes substances that are formed during metabolism. In pathologies, it is enriched with substances that ideally should not be in the body. Thanks to their presence, it is possible to identify the pathological process.
Now you know not only why the blood in the veins is darker than the arterial blood, but also why blood is taken from the vein.
Anyone can determine the type of bleeding; there is nothing difficult about it. The main thing is to know the characteristics of biological fluid. Venous blood has a darker shade (why venous blood is darker than arterial blood is indicated above), and it is also much thicker. When cut, it flows out in a slow stream or drops. But as for the arterial one, it is liquid and bright. When wounded, it sprays like a fountain.
Stop venous bleeding It’s simpler, sometimes it stops on its own. Typically, a tight bandage is used to stop bleeding (placed below the wound).
As for arterial bleeding, everything is much more complicated. It is dangerous because it does not stop on its own. In addition, blood loss can be so large that death can occur literally within an hour.
Capillary bleeding can open even with minimal injury. The blood flows out calmly, in a small stream. Similar damage treated with brilliant green. Next, a bandage is applied to them, which helps stop bleeding and prevent pathogenic microorganisms into the wound.
As for the venous, when damaged, blood flows out somewhat faster. In order to stop bleeding, a tight bandage is applied, as already mentioned, below the wound, that is, further from the heart. Next, the wound is treated with 3% peroxide or vodka and bandaged.
As for the arterial one, it is the most dangerous. If you have already been injured and you see bleeding from the artery, you must immediately raise the limb as high as possible. Next, you need to bend it and pinch the wounded artery with your finger.
Then a rubber tourniquet (rope or bandage will do) is applied above the wound site, after which it is tightened tightly. The tourniquet must be removed no later than two hours after application. While the bandage is being applied, a note is attached indicating the time of application of the tourniquet.
Bleeding is dangerous and can lead to severe blood loss and even fatal. That is why in case of injury it is necessary to call ambulance or take the patient to the hospital yourself.
Now you know why the blood in the veins is darker than the blood in the arteries. Blood circulation is a closed system, which is why the blood in it is either arterial or venous.
The blood that constantly circulates in the body is not the same everywhere. In some areas vascular system it is venous, on others it is arterial. What is this substance in each case, and how does venous blood differ from arterial blood? This is discussed below.
General information
Among the functions of blood, the most important is supplying nutrition and oxygen to tissues, as well as freeing the body from metabolic products. All this movement of vital fluid occurs along a closed trajectory. In this case, there is a division of the system into two sectors, called circulatory circles. Small - passes through the lungs, where oxygen enters the blood. Large - permeates the entire body, its organs and tissues.
The beats of the heart make the blood move. The most large vessels come directly from this body. Gradually they narrow, branch and turn into capillaries. Arteries, veins and smaller vessels are depicted below and the movement of blood is shown:
Comparison
Each type of blood has its own composition. Arterial- This is the one that is saturated with oxygen. In addition, it contains sufficient quantity useful elements because it nourishes the cells of the body. In a large circle, such blood flows, respectively, through the arteries, in the direction from the heart. But in small things, despite the name, through the veins.
Everything happens the other way around in the case of venous blood. In the large circle it moves to the main organ through the veins, and in the small circle it moves from the heart to the lungs through the arteries. Such blood carries a lot of carbon dioxide and metabolic products, but there are practically no nutrients in it. Arterial blood turns into a liquid with the specified composition after recoil useful components body tissues. Thus, an important substance, circulating along a closed path, regularly changes its type when passing through certain sections.
Let us name other signs that make up the difference between venous blood and arterial blood. The visual differentiating factor is color. U venous blood it is deep, dark red with a cherry tint. Arterial fluid, in turn, is brighter. It was revealed that her temperature was slightly lower.
Another feature by which comparison can be made is the speed of movement of the train of both types. Thus, venous blood has a more measured flow. This is also explained by the action of some physical strength, and the fact that the veins are equipped with valves that control such movement. By the way, these vessels are clearly visible under the skin in certain areas of the body, for example in the wrist area.
Because of low pressure venous blood, which is also thicker, comes out calmly when the body is damaged. It's easier to stop her. Meanwhile with arterial bleeding, which has an intense pulsating nature, is very difficult to cope with. This phenomenon is very dangerous for human life.
What is the difference between venous and arterial blood? The fact is that when determining diseases, the first type of material is more often collected. After all, it is venous blood, saturated with waste products, that can tell more about any problems in the body.