How is venous blood different from arterial blood? Venous and arterial blood Why arterial blood.
Blood constantly circulates throughout the body, providing the transport of various substances. It consists of plasma and suspension of various cells (the main ones are erythrocytes, leukocytes and platelets) and moves along a strict route - the system of blood vessels.
Venous blood - what is it?
Venous - blood that returns to the heart and lungs from organs and tissues. It circulates through the pulmonary circulation. The veins through which it flows lie close to the surface of the skin, so the venous pattern is clearly visible.
This is partly due to a number of factors:
- It is thicker, saturated with platelets, and if damaged, venous bleeding is easier to stop.
- The pressure in the veins is lower, so when the vessel is damaged, the volume of blood loss is lower.
- Its temperature is higher, so in addition it prevents the rapid loss of heat through the skin.
The same blood flows in both arteries and veins. But its composition is changing. From the heart, it enters the lungs, where it is enriched with oxygen, which transfers to internal organs providing them with food. The veins that carry arterial blood are called arteries. They are more elastic, the blood moves through them in jerks.
Arterial and venous blood do not mix in the heart. The first passes on the left side of the heart, the second - on the right. They are mixed only with serious pathologies of the heart, which entails a significant deterioration in well-being.
What is the systemic and pulmonary circulation?
The contents are expelled from the left ventricle and enter the pulmonary artery where it is saturated with oxygen. Then, through the arteries and capillaries, it spreads throughout the body, carrying oxygen and nutrients.
The aorta is the largest artery, which then divides into superior and inferior. Each of them supplies blood to the upper and lower parts of the body, respectively. Since the arterial “flows around” absolutely all organs, is supplied to them with the help of an extensive system of capillaries, this circle of blood circulation is called large. But the volume of the arterial at the same time is about 1/3 of the total.
Blood flows through the pulmonary circulation, which gave up all the oxygen, and "took" metabolic products from the organs. It flows through the veins. The pressure in them is lower, the blood flows evenly. Through the veins, it returns to the heart, from where it is then pumped to the lungs.
How are veins different from arteries?
Arteries are more elastic. This is due to the fact that they need to maintain a certain rate of blood flow in order to deliver oxygen to the organs as quickly as possible. The walls of the veins are thinner, more elastic. This is due to a lower blood flow rate, as well as a large volume (venous is about 2/3 of the total volume).
What kind of blood is in the pulmonary vein?
The pulmonary arteries provide oxygenated blood to the aorta and its further circulation through the systemic circulation. The pulmonary vein returns some of the oxygenated blood to the heart to feed the heart muscle. It is called a vein because it brings blood to the heart.
What is saturated in venous blood?
Coming to the organs, the blood gives them oxygen, in return it is saturated with metabolic products and carbon dioxide, and acquires a dark red hue.
A large amount of carbon dioxide is the answer to the question why venous blood is darker than arterial blood and why veins are blue. It also contains nutrients that are absorbed in the digestive tract, hormones and other substances synthesized by the body.
Venous blood flow depends on its saturation and density. The closer to the heart, the thicker it is.
Why are tests taken from a vein?
This is due to the fact that the blood in the veins is saturated with metabolic products and the vital activity of organs. If a person is sick, it contains certain groups of substances, the remains of bacteria and other pathogenic cells. In a healthy person, these impurities are not found. By the nature of impurities, as well as by the level of concentration of carbon dioxide and other gases, it is possible to determine the nature of the pathogenic process.
The second reason is that venous bleeding during a vessel puncture is much easier to stop. But there are times when bleeding from a vein does not stop for a long time. This is a sign of hemophilia, a low platelet count. In this case, even a small injury can be very dangerous for a person.
How to distinguish venous bleeding from arterial:
- Assess the volume and nature of the flowing blood. The venous one flows out in a uniform stream, the arterial one is thrown out in portions and even "fountains".
- Assess what color the blood is. Bright scarlet indicates arterial bleeding, dark burgundy indicates venous bleeding.
- Arterial is more liquid, venous is thicker.
Why does the venous fold faster?
It is thicker, contains a large number of platelets. A low blood flow rate allows the formation of a fibrin network at the site of damage to the vessel, for which platelets “cling”.
How to stop venous bleeding?
With a slight damage to the veins of the limbs, it is enough to create an artificial outflow of blood by raising an arm or leg above the level of the heart. A tight bandage should be applied to the wound itself to minimize blood loss.
If the injury is deep, a tourniquet should be applied to the area above the injured vein to limit the amount of blood flowing to the injury site. In summer it can be kept for about 2 hours, in winter - for an hour, a maximum of one and a half. During this time, you need to have time to deliver the victim to the hospital. If you keep the tourniquet longer than the specified time, tissue nutrition will be disturbed, which threatens with necrosis.
It is advisable to apply ice to the area around the wound. This will help slow down the circulation.
Video
Both biological fluids are involved in all vital processes and ensure the normal functioning of the body.
The difference between venous and arterial blood
How is venous blood different from arterial blood? The first type of blood flow solves two main tasks - reservoir and transport, while the second provides only the delivery function.
Other differences lie in the principle of movement, chemical composition and shades of blood.
by color
Venous fluid is rich red, almost cherry in color. Such a tone is given to it by decay products and carbon dioxide, with which the substance is enriched as a result of tissue metabolism.
The fluid in the arteries is rich in hemoglobin and oxygen, which is why it acquires a scarlet hue.
Composition
The venous substance, in addition to carbon dioxide and waste products of the body, contains useful substances that are broken down in the gastrointestinal tract. Also, the composition of the blood substance includes reduced hemoglobin, colloidal components and hormones synthesized by the endocrine systems.
Arterial blood is cleared of metabolic products and is rich in compounds that are important for the body, obtained in the gastrointestinal tract: oxyhemoglobin, methemoglobin, salts and proteins.
On the move
Arterial blood moves from the heart to the cells under high pressure. Ejected from the left heart ventricle into the aorta, which breaks up into vessels and arterioles, the liquid substance penetrates into the capillaries, where oxygen and useful compounds are released into the cells. From there, the blood receives metabolic products and carbon dioxide.
Venous fluid flows in the opposite direction - towards the heart. Its pressure is much less than arterial pressure, since the flow has to overcome gravity and flow through the valves. Balance with bright red blood in the heart and vascular system is achieved due to the greater width and number of veins and the presence of a portal trunk in the liver.
Thanks to a branched system, the venous substance enters the heart through 3 large vessels and several small ones, and flows out through the pulmonary artery.
By function
The blood in the veins performs the function of cleaning, as it collects and removes decay products and other toxic substances from the body. At the same time, it serves as a kind of depot of nutrients and enzymes.
Arterial blood plays a transport role. It passes through all the cells of the body, saturating them with oxygen, stimulating metabolism and regulating some functions: respiratory, nutritional, homeostatic, protective.
By bleeding
It is not difficult to determine the type of external outflow from the vascular system. With venous blood loss, the substance comes out in a thick, slow stream. It is dark, almost black in color and stops on its own after a while.
With arterial bleeding, the liquid beats with a fountain or splashes out with powerful shocks, obeying the contractions of the heart. To cope with such an outflow is difficult, and sometimes impossible without the help of doctors. The condition can be life-threatening. With internal blood loss, a liquid substance spills between organs or into the abdominal cavity. The patient's condition deteriorates sharply, the skin turns pale and covered with sweat, loss of consciousness is possible.
Other differences
Another difference is that blood is often taken from a vein to determine the disease and make a diagnosis. It is she who can tell about all the problems in the body.
Where does venous blood turn into arterial blood?
The transformation of one substance into another occurs in the lungs. At the moment of receiving oxygen and giving off carbon dioxide, the blood fluid becomes arterial and continues its way through the body.
Isolation of flows is achieved by a perfect system of valves working in one direction, so the liquids never mix anywhere.
The division of blood into arterial and venous is carried out according to 2 signs - the mechanism of its movement and the physical properties of the substance itself. However, these two indicators contradict each other - arterial fluid moves through the veins of the small circle, and venous fluid moves through the arteries. Therefore, the defining moment should be considered the properties and composition of the blood.
Useful video about the anatomy of the circulatory system
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? This is discussed below.
General information
Among the functions of the blood, the most important is the supply of food and oxygen to the tissues, as well as the release of 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 circles of blood circulation. Small - passes through the lungs, where oxygen enters the blood. Large - permeates the entire body, its organs and tissues.
The heart beats make the blood move. The largest vessels come directly from this organ. Gradually, they narrow, branch and pass into the capillaries. The arteries, veins and smaller vessels are shown below and the movement of blood is shown:
Comparison
Each type of blood has its own composition. Arterial is the one that is oxygenated. In addition, it contains a sufficient amount of useful elements, as 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 the small, despite the name, - through the veins.
Everything happens the other way around in the case of venous blood. In a large circle, it moves to the main organ through the veins, and in a small circle, it goes 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 all kinds of nutrients in it. Arterial blood turns into a liquid with the specified composition after the return of useful components to the tissues of the body. Thus, an important substance, circulating along a closed path, regularly, when passing through certain sections, changes its type.
Let us name other signs that make up the difference between venous and arterial blood. Visually, the differentiating factor is color. At venous blood it is deep, dark red with a cherry tint. The arterial fluid, in turn, is brighter. It is revealed that its temperature is somewhat lower.
Another feature by which comparison can be made is the speed of movement of the composition of both types. So, venous blood has a more measured course. This is due to the action of some physical forces, 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.
Due to the low pressure, venous blood, which is also thicker, comes out calmly when the body is injured. It's easier to stop her. Meanwhile, it is very difficult to cope with arterial bleeding, which has an intense pulsating character. This phenomenon is very dangerous for human life.
What is the difference between venous and arterial blood? The fact that when determining diseases, the material of the first type is more often taken. After all, it is venous blood, saturated with waste products, that can tell more about any problems in the body.
Blood is designed to carry substances necessary for the functioning of cells, tissues and organs. The removal of decay products also occurs with the help of this liquid. These two different functions within the same system are carried out through the arteries and veins. The blood flowing through these vessels contains different substances, which leaves its mark on the appearance and properties of the contents of the arteries and veins. Arterial blood, venous blood represent a different state of a single transport system of our body, providing a balance of biosynthesis and destruction of organic matter in order to obtain energy.
Venous and arterial blood move through different vessels, but this does not mean that they exist in isolation from each other. These names are conditional. Blood is a liquid that flows from one vessel to another, penetrates into the intercellular space, returning again to the capillaries.
Its division into types is more functional than structural character.Functional
The functions of the blood can be divided into two parts - general and specific. Common features include:
- thermoregulation of the body;
- transportation of hormones;
- transfer of nutrients from the digestive system.
Human venous blood, unlike arterial blood, contains an increased amount of carbon dioxide and very little oxygen.
Venous blood differs from arterial blood in proportions of two gases for the reason that CO2 enters all vessels, and O2 only enters the arterial part. circulatory system.by color
Distinguish by appearance arterial blood from venous very easy. In the arteries, it is light and bright red. The color of venous blood can also be called red. However, brownish shades predominate here.
This difference is due to the state of hemoglobin. Oxygen enters into an unstable combination with hemoglobin iron in erythrocytes. Oxidized iron takes on a bright red rust color. Venous blood contains a lot of hemoglobin with free iron ions.
There is no rust color here, because the iron is again in a state free of oxygen.On the move
Blood moves in the arteries under the influence of heartbeats, and in the veins its flow is directed in the opposite direction, that is, towards the heart. In this part of the circulatory system, the rate of blood movement in the vessels becomes even slower. The presence of valves in the veins also contributes to a decrease in speed, which prevent the occurrence of a reverse flow in the veins.
Ask your question to the doctor of clinical laboratory diagnostics
Anna Poniaeva. She graduated from the Nizhny Novgorod Medical Academy (2007-2014) and residency in clinical laboratory diagnostics (2014-2016).
Venous blood flows from the heart through the veins. It is responsible for moving carbon dioxide around the body, which is necessary for blood circulation. The main difference between venous and arterial blood is that it has more high temperature and contains fewer vitamins and minerals.
Arterial blood flows in capillaries. These are the smallest points on the human body. Each capillary carries a certain amount of fluid. The entire human body is divided into veins and capillaries. There is a certain kind of blood flowing there. Capillary blood gives a person life and provides oxygen throughout the body and most importantly in the heart. 
Arterial blood is red and flows throughout the body. The heart pumps it to all the remote corners of the body, so that it circulates everywhere. Its mission is to saturate the whole body with vitamins. This process keeps us alive.
Venous blood is blue-red in color, contains metabolic products, flows through veins with very thin walls. She can withstand the impact high pressure, because the heart at the time of contraction, drops can form that the vessels must withstand. The veins are located above the arteries. They are easy to see on the body and easier to damage. On the other hand, venous blood is thicker than arterial blood and flows out more slowly.
The most severe wounds for a person are cardiac and inguinal. These places must always be protected. All the blood in a person flows through them, therefore, with the slightest damage, a person can lose all the blood.
There is a large and small circles of blood circulation. In a small circle, the fluid is saturated with carbon dioxide and flows to the lungs from the heart. It leaves the lungs, having been saturated with oxygen, and enters big circle. From the lungs to the heart runs blood based on carbon dioxide, through the capillaries of the lungs carry blood based on vitamins and oxygen. 
Oxygenated blood is located on the left side of the heart, and venous blood is located on the right side. During the contraction of the heart, arterial blood enters the aorta. It is the main vessel of the body. From there, oxygen enters down and ensures the functioning of the legs. The aorta is the most important artery for humans. She, like her heart, cannot be damaged. This can lead to rapid death.
The role and functions of venous blood
Venous blood is often used for human research. It is believed that it speaks better about human diseases, because it is a consequence of the work of the body as a whole. In addition, blood from a vein is not difficult to take, because it flows worse than a capillary, so a person will not lose much blood during the operation. The largest human arteries cannot be damaged at all, and if necessary, an examination of arterial blood is taken from the finger to minimize negative consequences for the body.
Venous blood is used by doctors to prevent diabetes. It is necessary that the level of sugar in the veins does not exceed 6.1. Arterial blood is a clear liquid that flows throughout the body, nourishing all organs. Venous absorbs the waste products of the body, cleaning it. Therefore, it is by this type of blood that human diseases can be determined.
Bleeding can be external and internal. The internal is more dangerous for the body and occurs when human tissues are damaged from the inside. Most often, this occurs after a very deep external wound or a malfunction in the body that has led to tissue rupture from the inside. Blood begins to flow into the crack, and the body feels oxygen starvation. The person begins to turn pale and loses consciousness. This is due to the fact that too little oxygen is supplied to the brain. Venous blood can be lost due to internal bleeding and it will be harmless to a person, while arterial blood is not. Internal bleeding quickly blocks brain function due to lack of oxygen. With external bleeding, this will not happen, because the connection between human organs is not broken. Although, the loss of a large amount of blood is always fraught with loss of consciousness and death.
Summary
So, the main difference between venous blood and arterial blood is this color. Venous blue and arterial red. The venous is rich in carbon dioxide, and the arterial is rich in oxygen. Venous flows from the heart to the lungs, where it turns into an arterial, saturated with oxygen. Arterial flows through the aorta from the heart throughout the body. Venous blood contains metabolic products and glucose, arterial blood is more salty.
Arterial blood is located on the left in the heart, venous on the right. The blood must not mix. If this happens, it will increase the load on the heart and reduce the physical capabilities of a person. In lower animals, the heart consists of one chamber, which inhibits their development.
Both types of blood are very important for a person. One feeds it, and the other collects harmful substances. In the process of blood circulation, blood passes one into another, which ensures the functioning of the body and the structure of the body that is optimal for life. The heart pumps blood at a tremendous speed and does not stop working, even during sleep. It's very hard for him. The division of blood into two types, each of which performs its own functions, allows a person to develop and improve. Such a structure of the circulatory system helps us to remain the most intelligent among all creatures born on Earth.