Dark blood is venous or arterial. How to distinguish venous bleeding from arterial bleeding. Systemic circulation

Blood performs in the body important function– provides all organs and tissues with oxygen and various useful substances. From the cells she takes carbon dioxide, decomposition products. There are several types of blood: venous, capillary and arterial blood. Each type has its own function.

General information

For some reason, almost all people are sure that arterial blood is the type that flows in arterial vessels. In fact, this opinion is wrong. Arterial blood is enriched with oxygen, which is why it is also called oxygenated. It moves from the left ventricle to the aorta, then goes through the arteries of the systemic circulation. After the cells are saturated with oxygen, the blood turns into venous and enters the veins of the BC. In a small circle, arterial blood moves through the veins.

Different types of arteries are located in different places: some are deep in the body, while others allow you to feel the pulsation.

Venous blood moves through the veins into the CD and through the arteries into the MC. There is no oxygen in it. This liquid contains a large amount of carbon dioxide, decay products.

Differences

Venous and arterial blood are different. They differ not only in function, but also in color, composition and other indicators. These two types of blood have differences in bleeding. First aid is provided in different ways.

Function

Blood has a specific and general functions. The latter include:

• nutrient transfer;
• transport of hormones;
• thermoregulation.

IN venous blood a lot of carbon dioxide and little oxygen. This difference is due to the fact that oxygen enters only the arterial blood, while carbon dioxide passes through all vessels and is contained in all types of blood, but in different quantities.

Color

Venous and arterial blood has different colour. In the arteries it is very bright, scarlet, light. The blood in the veins is dark, cherry-colored, almost black. This is related to the amount of hemoglobin.

When oxygen enters the blood, it enters into an unstable combination with the iron contained in red blood cells. Once oxidized, iron colors the blood bright red. Venous blood contains many free iron ions, which is why it becomes dark in color.

Blood movement

When wondering what the difference is between arterial blood and venous blood, few people know that these two types also differ in their movement through the vessels. In arteries, blood moves away from the heart, and through veins, on the contrary, towards the heart. In this part circulatory system blood circulation is slow as the heart pushes fluid away from itself. Valves located in the vessels also affect the reduction in movement speed. This type blood movement occurs in the systemic circulation. In the pulmonary circle, arterial blood moves through the veins. Venous - through the arteries.

In textbooks, on schematic representation blood circulation, arterial blood is always colored red, and venous blood is always blue. Moreover, if you look at the diagrams, the number of arterial vessels corresponds to the number of venous ones. This image is approximate, but it fully reflects the essence of the vascular system.

The difference between arterial blood and venous blood also lies in the speed of movement. The arterial is ejected from the left ventricle into the aorta, which branches into smaller vessels. Then the blood enters the capillaries, nourishing all organs and systems cellular level useful substances. Venous blood collects from capillaries into larger vessels, moving from the periphery to the heart. When the fluid moves, it is observed different pressure on various areas. Arterial blood pressure is higher than that of venous blood. It is ejected from the heart under a pressure of 120 mm. rt. Art. In the capillaries the pressure drops to 10 millimeters. It also moves slowly through the veins, since it has to overcome the force of gravity and cope with the system of vascular valves.

Due to the difference in pressure, blood for testing is taken from capillaries or a vein. Blood is not taken from the arteries, since even minor damage to the vessel can provoke extensive bleeding.

Bleeding

When providing first aid, it is important to know which blood is arterial and which is venous. These species are easily identified by their flow patterns and color.

With arterial bleeding, a fountain of bright scarlet blood is observed. The liquid flows out pulsatingly and quickly. This type of bleeding is difficult to stop, which is the danger of such injuries.

When providing first aid, it is necessary to raise the limb and compress the damaged vessel by applying a hemostatic tourniquet or pressing it with finger pressure. In case of arterial bleeding, the patient must be taken to the hospital as quickly as possible.

Arterial bleeding may be internal. In such cases, a large amount of blood enters the abdominal cavity or various organs. With this type of pathology, a person suddenly becomes ill, skin turn pale. After some time, dizziness and loss of consciousness begin. This is due to lack of oxygen. Only doctors can provide assistance with this type of pathology.

With venous bleeding, dark cherry-colored blood flows out of the wound. It flows slowly, without pulsation. You can stop this bleeding yourself by applying a pressure bandage.

Circulation circles

There are three circles of blood circulation in the human body: large, small and coronary. All the blood flows through them, so even if damaged small vessel Severe blood loss may occur.

The pulmonary circulation is characterized by the release of arterial blood from the heart, passing through the veins to the lungs, where it is saturated with oxygen and returns back to the heart. From there it goes along the aorta in a large circle, delivering oxygen to all tissues. Passing through various organs, the blood is saturated nutrients, hormones that travel throughout the body. In the capillaries there is an exchange of useful substances and those that have already been used. This is where oxygen exchange occurs. From the capillaries the fluid enters the veins. At this stage, it contains a lot of carbon dioxide, decay products. Through the veins, venous blood is carried throughout the body to organs and systems, where cleansing of harmful substances occurs, then the blood approaches the heart, passes into a small circle, where it is saturated with oxygen, giving off carbon dioxide. And everything starts all over again.

Venous and arterial blood should not mix. If this happens, it will reduce physical abilities person. Therefore, in case of heart pathologies, operations are performed that help to normal image life.

For human body Both types of blood are important. During blood circulation, fluid changes from one type to another, ensuring the normal functioning of the body, as well as optimizing the functioning of the body. The heart pumps blood at tremendous speed, without stopping its work for a minute, even during sleep.

The vascular system maintains constancy in our body, or homeostasis. She helps him in the processes of adaptation, with her help we withstand significant physical exercise. Prominent scientists, since ancient times, have been interested in the structure and operation of this system.

If we imagine the circulatory apparatus as a closed system, then its main components will be two types of vessels: arteries and veins. Each performs a specific set of tasks and transfers different types blood. How venous blood differs from arterial blood will be discussed in the article.

The task of this type is the delivery of oxygen and useful substances to organs and tissues. She flows from the heart, rich in hemoglobin.

The color of arterial and venous blood is different. The color of arterial blood is bright red.

The largest vessel through which it moves is the aorta. She is characterized by high speed movements.

If bleeding occurs, stopping it requires effort due to its pulsating nature under high pressure. The pH is higher than that of the venous one. On the vessels through which this type moves, doctors measure the pulse(on the carotid or radial).

Deoxygenated blood

Venous blood is the one that flows back from the organs to return carbon dioxide. It doesn't have useful microelements, carries very low concentration O2. But it is rich in metabolic end products and contains a lot of sugar. It is characterized by a higher temperature, hence the expression “warm blood.” To conduct laboratory diagnostic measures that's what they use. All medications nurses administer through veins.

Human venous blood, unlike arterial blood, has dark color, burgundy. The pressure in the venous bed is low, the bleeding that develops when the veins are damaged is not intense, the blood oozes out slowly, and is usually stopped with a pressure bandage.

To prevent its reverse movement, the veins have special valves that prevent backward flow; the pH is low. There are more veins in the human body than arteries. They are located closer to the surface of the skin and are clearly visible visually in people with a light color type.

Once again about the differences

The table shows Comparative characteristics what arterial and venous blood is.

Attention! Most frequently asked question- Which blood is darker: venous or arterial? Remember - venous. It is important not to confuse this when getting into emergency. With arterial bleeding, the risk of losing a large volume in a short period of time is very high, and there is a threat fatal outcome, urgent measures need to be taken.

Circulation circles

At the beginning of the article, it was noted that blood moves in the vascular system. From school curriculum Most people know that movement is circular, and there are two main circles:

1. Big (BKK).
2. Small (MCC).

In mammals, including humans, the heart has four chambers. And if you add up the length of all the vessels, you get a huge figure - 7 thousand square meters.

But it is precisely this area that makes it possible to supply the body with O2 in the required concentration and not cause hypoxia, that is oxygen starvation.

BCC begins in the left ventricle, from which the aorta emerges. It is very powerful, with thick walls, with a strong muscle layer, and its diameter in an adult reaches three centimeters.

It ends in the right atrium, into which 2 vena cava flow. The ICC originates in the right ventricle from the pulmonary trunk, and closes in the left atrium with the pulmonary arteries.

Oxygen-rich arterial blood flows in a large circle, it is directed to each organ. As they progress, the diameter of the vessels gradually decreases to very small capillaries, which give away everything useful. And back, along the venules, gradually increasing their diameter to large vessels, such as the superior and inferior vena cava, the depleted venous flows.

Once in right atrium, through a special hole, it is pushed into the right ventricle, from which the small circle, pulmonary, begins. The blood reaches the alveoli, which enrich it with oxygen. Thus, venous blood becomes arterial!

Something very surprising happens: arterial blood moves not through arteries, but through veins - pulmonary veins, which flow into left atrium. Blood saturated with a new portion of oxygen enters the left ventricle and the circles are repeated again. That's why the statement that venous blood moves through the veins is incorrect, here everything works the other way around.

Fact! In 2006, a study was conducted on the functioning of the BCC and MCC in people with poor posture, namely scoliosis. Attracted 210 people under 38 years of age. It turned out that in the presence of scoliotic disease, there is a disruption in their work, especially among adolescents. In some cases, requiring surgical treatment.

For some pathological conditions Possible disruption of blood flow, namely:

• organic heart defects;
• functional;
• pathologies of the venous system: , ;
• , autoimmune processes.

Normally there should be no mixing. During the neonatal period, there are functional defects: open oval window, open Batalov duct.

After a certain period of time, they close on their own, do not require treatment and are not life-threatening.

But severe valve defects, reversal of the main vessels, or transposition, absence of a valve, weakness of the papillary muscles, absence of a heart chamber, combined defects– life-threatening conditions.

That is why, to the expectant mother it is important to undergo screening ultrasound examinations fetus during pregnancy.

Conclusion

The functions of both types of blood, arterial and venous, are undeniably important. They maintain balance in the body and ensure its full functioning. And any violations contribute to a decrease in endurance and strength, and worsen the quality of life.

Good afternoon, Mikhail!

The blood “in the body,” as you put it, is arterial blood. It is fundamentally different from venous in appearance, place of circulation in the human body and composition.

External blood parameters

The composition of arterial blood includes hemoglobin, oxidized by particles of oxygen in the blood, which is called oxyhemoglobin. This component gives arterial blood a bright red and even scarlet hue. Venous blood does not contain oxygen, it is enriched with carbon dioxide, which is why it acquires a dark red, almost burgundy color. In this case, venous blood is warmer than arterial blood.

Composition of arterial and venous blood

Lab tests make it possible to distinguish arterial blood samples from venous blood by its composition. Normally in a person with good condition health, the oxygen tension in arterial blood is from 80 to 100 mmHg. It also contains carbon dioxide molecules. Its indicators range from 35 to 45 mmHg. In venous blood, the ratio of oxygen and carbon dioxide is exactly the opposite. Thus, the oxygen tension in venous blood is normally about 38 - 42 mm Hg, and carbon dioxide - 50 - 55 mm Hg. In addition to gases, arterial blood contains a large amount of nutrients, while venous blood is dominated by cellular waste products, which are then adsorbed in the liver and kidneys. Laboratory tests show that the pH of arterial blood is 7.4, and venous blood is 7.35.

Functions of arterial and venous blood

The main function of arterial blood is to transport oxygen particles to the organs and tissues of the human body through the arteries of the systemic circulation and the veins of the pulmonary circulation. Arterial blood passes through all tissues of the body, delivering oxygen molecules necessary for metabolism. Gradually losing oxygen particles, it is filled with carbon dioxide molecules and turns into a venous type.

The venous system carries out the outflow of blood enriched with carbon dioxide and metabolic products. In addition, it contains hormones produced by the glands internal secretion, and nutrients that are absorbed by the walls of the digestive organs, i.e. a large number of metabolic end products.

Blood movement

Arterial blood moves away from the heart, and venous blood moves towards the heart. Blood circulation through veins is significantly different from blood circulation through arteries. Normally, when contracting, the heart ejects arterial blood at a pressure of 120 mmHg. Then, passing through the capillary network, the ejection force gradually decreases, and the pressure drops to 10 mmHg. Accordingly, venous blood moves much slower than arterial blood. Moreover, in venous system the blood moves, overcoming the force of gravity and experiencing the fullness of hydrostatic pressure. Because of this, arterial bleeding is easy to distinguish from venous bleeding. When arteries are damaged, the blood “spouts”, pulsates, and venous blood flows slowly.

Best regards, Ksenia.

Venous blood flows from the heart through the veins. It is responsible for moving carbon dioxide throughout the body, which is necessary for blood circulation. The main difference between venous blood and arterial blood is that it has a higher temperature and contains less vitamins and microelements.

Arterial blood flows in capillaries. These are the smallest points on the human body. Each capillary carries a certain amount of liquid. The entire human body is divided into veins and capillaries. It's flowing there certain type blood. Capillary blood gives a person life and ensures the flow of oxygen throughout the body and most importantly to the heart.

Arterial blood is red and flows throughout the body. The heart pumps it to all remote corners of the body, so that it circulates everywhere. Its mission is to saturate the entire body with vitamins. This process keeps us alive.

Venous blood is blue-red in color, contains metabolic products, and flows through veins with very thin walls. She withstands the impact high pressure, because when the heart contracts, drops can form that the vessels must withstand. Veins are located above the arteries. They are easy to see on the body and easier to damage. But venous blood is thicker than arterial blood and flows out more slowly.

The most severe wounds for humans are the heart and groin. These places must always be protected. All the blood in a person flows through them, so when the slightest damage a person may lose all his blood.

There is a large and small circle of blood circulation. In the small circle, the liquid is saturated with carbon dioxide and flows to the lungs from the heart. It leaves the lungs, saturated with oxygen, and enters a large circle. Blood, based on carbon dioxide, runs from the lungs to the heart; through the capillaries, 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. During the contraction of the heart, arterial blood enters the aorta. This main vessel body. From there, oxygen flows down and ensures the functioning of the legs. The aorta is the most important artery for humans. It, like the 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, it is not difficult to take blood from a vein, because it flows worse than a capillary, so a person will not lose much blood during the operation. The largest human arteries should not be damaged at all, and if it is necessary to do a study of arterial blood, it is taken from a finger in order to minimize the negative consequences for the body.

Venous blood is used by doctors for prevention diabetes mellitus. It is necessary that the level of sugar in the veins does not exceed 6.1. Arterial blood is a pure liquid that flows throughout the body, nourishing all organs. Venous absorbs the waste products of the body, cleansing it. Therefore, it is by this type of blood that human diseases can be determined.

Bleeding can be external and internal. Internal is more dangerous for the body and occurs when human tissue is damaged with inside. Most often, this occurs after a very deep external wound or a malfunction in the body leading 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 occurs because too little oxygen reaches the brain. Venous blood can be lost due to internal bleeding and this will be harmless to humans, but arterial blood is not. Internal bleeding quickly blocks brain function due to lack of oxygen. This will not happen with external bleeding, because the connection between human organs is not disrupted. Although, loss large quantity 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 is blue, and arterial is red. Venous is rich in carbon dioxide, and arterial is rich in oxygen. Venous flows from the heart to the lungs, where it turns into arterial, saturated with oxygen. The arterial flows through the aorta from the heart throughout the body. Venous blood contains metabolic products and glucose, arterial blood is saltier.

Arterial blood is located on the left side of the heart, venous blood on the right. Blood should not mix. If this happens, it will increase the load on the heart and reduce a person's physical capabilities. In lower animals, the heart consists of one chamber, which inhibits their development.

Both types of blood are very important for humans. One feeds it, and the other collects it harmful substances. In the process of blood circulation, blood passes one into another, which ensures the functioning of the body and the optimal structure of the body for life. The heart pumps blood at high speed and does not stop working, even during sleep. This is very difficult for him. The division of blood into two types, each of which performs its own functions, allows a person to develop and improve. This structure of the circulatory system helps us remain the most intelligent among all creatures born on Earth.

Blood in the human body circulates in a closed system. The main function of biological fluid is to provide cells with oxygen and nutrients and remove carbon dioxide and metabolic products.

A little about the circulatory system

The human circulatory system has a complex structure; biological fluid circulates in the pulmonary and systemic circulation.

The heart, which acts as a pump, consists of four sections - two ventricles and two atria (left and right). The vessels that carry blood from the heart are called arteries, and the vessels that carry blood 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 the thickest, contracts, maximum pressure is created, 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 blood, rich in oxygen. 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 hormones produced by the endocrine glands.

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?

Venous blood contains breakdown products formed during the metabolic process. 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. Usually required pressure bandage, applied below the wound. If a vein in the arm is damaged, it may be enough to raise the arm up.

Concerning arterial bleeding, then 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.