Venous and arterial blood. Which vessels carry the darker blood and how does the circulatory system work?

Only under the influence of enzymes. Hemoglobin promotes the transport of oxygen from the lungs to various organs and tissues. The difference in the color of the blood is due to the unequal oxygen content in its cells. One of the types of blood vessels are arteries. They carry blood from the lungs and heart to other organs and tissues. This blood is saturated, which, in turn, combines with hemoglobin, giving the blood a bright red color. Arterial blood is distributed through capillaries and small, thin-walled blood vessels that carry oxygen and nutrients to all other cells in the body. The metabolic product produced by cells is carbon dioxide. It enters the blood through the walls of the capillaries. From the capillaries, this rich blood enters the veins, which are another type of blood vessel. Through the veins, blood enters the lungs and heart. The dark red, almost burgundy color of the blood is due to the lack of oxygen in it. In addition, red blood cells in size and lose their rich bright color. When the blood reaches the lungs, carbon dioxide enters them. At this moment, the brain receives a signal that carbon dioxide has accumulated, the brain gives the command to do it, and all carbon dioxide is released into the air. After that, the person takes a breath, the blood is again saturated with oxygen, and the process starts all over again.

Some diseases can be manifested not only by poor health, but also by various rashes on the body or discoloration of the skin. It is important to notice these changes in time and seek help from specialists.

Why is the skin around the eyes dark?

The skin around the eyes is thin and delicate. It is permeated with many capillaries through which blood flows. As a result of the rupture of a tiny vessel, blood flows out. Due to the process of freeing the body from leaked blood, dark circles appear. It enters the composition of the blood, in the process of oxidation, it breaks down into smaller components and acquires a purple or color. The same process is observed after a blow, a bruise.

Causes of dark circles under the eyes

An allergic reaction can cause black circles under the eyes. When your eyes water, you can't resist scratching them. Due to constant rubbing, capillary damage occurs, which entails such.

It happens that fatigue, lack of sleep, overstrain can appropriately transform the appearance. But this lifestyle is not the cause of the appearance of black circles, it only makes the skin pale, which further emphasizes the blackness under the eyes. But malnutrition, lack of vitamins and lack of rest together can negatively affect the skin around the eyes.

When talking with, you always look him in the eye. Noticing the black circles of the interlocutor, you change the impression of him. One gets the feeling that he is sick with something. It may be so. Kidney dysfunction, cardiovascular disease, lack of oxygen can affect the color of the skin around the eyes. To fix this, cosmetic procedures will not help, it is necessary to cure the disease.

If you find black spots under the eyes, you should consult a doctor to identify the cause. Perhaps this is the first sign of a serious illness.

The blame for everything can be old age, which spares no one. The skin becomes thinner, blood vessels become more visible. And the older a person gets, the more the process gets worse. By identifying the cause of the appearance of black circles under the eyes, the doctor can diagnose a lack of blood.

To increase the level of iron in the blood, you need to eat right, eat more fresh fruits, vegetables and natural juices.

It is especially necessary to carefully monitor the vision, eyes and condition of their skin for people who work a lot at the computer. Severe overstrain of the organs of vision - the appearance of circles under the eyes.

Various diseases and injuries can cause damage to blood vessels and lead to bleeding. To avoid major blood loss, it is very important to seek immediate medical attention.

The main causes of bleeding is an inflammatory process or neoplasm on the walls of blood vessels resulting from their mechanical damage or disease. It can also be caused by a violation of the integrity of the vessel wall caused by poisoning, infection, or a lack of vitamins. If we are talking about the causes of bleeding from, then this can be an increase in blood pressure, trauma, infectious and respiratory diseases. People often suffer from nosebleeds with sudden changes in atmospheric pressure, overheating, intense emotional and physical stress. The causes of internal bleeding of organs are usually a violation of the integrity of the intestine or the wall and mucous membrane. About fifty percent of this type of bleeding is provoked by an ulcer of the digestive organs. In addition, the outflow of blood from the rectum can be caused by a complicated diverticulum, oncological diseases of the colon or caecum, and chronic hemorrhoids. However, bleeding from the rectum is not always so dangerous, sometimes it can be caused by cracks in the anus or provoked by scratching in this area. Whatever the localization of bleeding, it is necessary to take into account the strength with which it flows, what it is. In case of bleeding from the anus, it is necessary to report other disturbing symptoms, for example, changes in stool, pain syndrome, etc. The presence of internal bleeding, which may be caused by bruising of internal organs, may not even be suspected for a long time. In such cases, gastric bleeding is especially dangerous, in which blood accumulates in the internal cavities. The signs of this condition include pallor of the skin and mucous membranes, general weakness, a rapid, weakly audible pulse, and low blood pressure. If we talk about uterine bleeding, then there are a lot of reasons for them. They can be caused by inflammation of the reproductive organs, dysfunction of the endocrine system, intoxication of the body, and even severe neuropsychic stress. Also, uterine bleeding can be provoked by the lack of rest during work, the presence of polyps and neoplasms of the uterus, the use of certain medicines.

Sources:

• Bleeding

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:

1. It is thicker, saturated with platelets, and if damaged, venous bleeding is easier to stop.
2. The pressure in the veins is lower, so when the vessel is damaged, the volume of blood loss is lower.
3. 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 it transfers to the internal organs, providing them with nutrition. 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?

From the left ventricle, the contents are pushed out and enter the pulmonary artery, where they are 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:

1. 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".
2. Assess what color the blood is. Bright scarlet indicates arterial bleeding, dark burgundy indicates venous bleeding.
3. 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

What you will not find on the net. Even the question of the color of blood and veins is often accompanied by assumptions and fiction, although most people actually know the answer to it. Yes, everything is simple here - the blood is red, only of different shades, depending on the amount of hemoglobin in it and oxygen enrichment. Everything as biology and BJD teaches at school: arterial blood(rich in oxygen coming from the heart) bright scarlet color, a venous(given oxygen to the organs, returning to the heart) - dark red(burgundy). The veins that are visible from under the skin are also red when blood runs through them inside. After all, the blood vessels themselves are quite transparent. But still, many people have questions such as “Why does blood come in different colors and what does it depend on?” and "Why are veins blue or blue?".

The red color of blood can have different shades. Oxygen carriers, that is, red blood cells (red blood cells), have a shade of red depending on hemoglobin, an iron-containing protein in them that can bind with oxygen and carbon dioxide to carry them to the right place. The more oxygen molecules attached to hemoglobin, the brighter the red color of the blood. Therefore, arterial blood, which has just been enriched with oxygen, is so bright red. After the release of oxygen to the cells of the body, the color of the blood changes to dark red (burgundy) - such blood is called venous.

Of course, there are other cells in the blood besides red blood cells. These are also leukocytes (white blood cells) and platelets. But they are not in such a significant amount compared to red blood cells to affect the color of the blood.

Blood color in anemia and cyanosis

In fact, of course, although the veins carry dark burgundy blood, unlike the bright scarlet arterial blood, they are by no means blue in color. They are red, like the color of the blood that flows through them. And do not believe in the theory that can be found on the Internet that the blood actually runs through the vessels is blue, and when cut and in contact with air it becomes instantly red - this is not so. Blood is always red, and why is described above in the article.

The veins only appear blue to us. This is due to the laws of physics about the reflection of light and our perception. When a beam of light hits the body, the skin beats off part of all the waves and therefore looks light, well, or different, depending on melanin. But she misses the blue spectrum worse than the red one. But the vein itself, or rather the blood, absorbs light of all wavelengths (but less, in the red part of the spectrum). That is, it turns out that the skin gives us a blue color for visibility, and the vein itself - red. But, interestingly, in fact, the vein reflects even a little more red than the skin of the blue spectrum of light. But why then do we see veins blue or light blue? And the reason, in fact, lies in our perception - the brain compares the color of a blood vessel against a bright and warm skin tone, and as a result shows us blue.

Why do we not see other vessels through which blood flows?

If the blood vessel is closer than 0.5 mm to the skin surface, then it generally absorbs almost all blue light, and beats off much more red light - the skin looks healthy pink (ruddy). If the vessel is much deeper than 0.5 mm, then it is simply not visible, because the light does not reach it. Therefore, it turns out that we see the veins, which are approximately located at a distance of 0.5 mm from the surface of the skin, and why they are blue has already been described above.

Why can't we see arteries from under the skin?

In fact, about two-thirds of the volume of blood is in the veins at all times, hence they are larger than other vessels. In addition, arteries have much thicker walls than veins, because they have to withstand more pressure, which also prevents them from being sufficiently transparent. But even if the arteries were visible from under the skin as well as some veins, it is assumed that they would have approximately the same color, despite the fact that the blood running through them is brighter.

What is the actual color of a vein?

If you've ever cooked meat, you probably already know the answer to this question. Empty blood vessels are reddish-brown in color. There is not much difference in color between arteries and veins. They differ mainly when viewed in cross section. Arteries are thick-walled and muscular, while veins have thin walls.

As for the aristocrats, the expression "blue blood" appeared due to the pallor of their skin. Until the twentieth century, tanning was not in vogue, and the aristocrats themselves, especially women, hid from the sun, which saved their skin from premature aging and looked according to their status, that is, they differed from serfs who “plowed” all day in the sun. It is now we realize that pale skin with a blue tint is actually a sign of lesser health.

But scientists also claim that there are about 7,000 people in the world whose blood has a blue tint. They are called kyanetics (from lat. cyanea - blue). The reason for this is not such hemoglobin. In them, this protein contains more copper than iron, which, during oxidation, acquires a blue tint instead of the usual red for us. These people are considered to be more resistant to many diseases and even injuries, as they say that their blood clots several times faster and is not exposed to many infections. In addition, there are various theories about the origin of Kyanetics, including that they are descendants of aliens. There is not much information about them on the net, but there are articles from foreign publications where the birth of such children is explained by the abuse of contraceptive drugs long before conception. As they say, “Don’t smoke, girl, the children will be green!”, And it can turn out blue from contraceptives (meaning the color of blood).

Blood in the human body circulates in a closed system. The main function of the 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, the biological fluid circulates in the pulmonary and systemic circulation.

The heart, acting as a pump, consists of four sections - two ventricles and two atria (left and right). Vessels that carry blood away from the heart are called arteries, and those that carry blood to the heart are called veins. Arterial is enriched with oxygen, venous - with carbon dioxide.

Thanks to the interventricular septum, venous blood, which is located in the right side of the heart, does not mix with arterial blood, which is in the right section. 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 largest artery (aorta) to the ventricle, and from the ventricle to the atrium.

With the contraction of the left ventricle, the walls of which are the thickest, maximum pressure is created, oxygen-rich blood is pushed into the systemic circulation and carried 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, the venous through the 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 in the right side of the heart

Characteristics

Venous blood differs in a number of parameters, ranging from its appearance to its functions.

• Many people know what color it is. Due to the saturation of carbon dioxide, its color is dark, with a bluish tint.
• It is poor in oxygen and nutrients, while it contains a lot of metabolic products.
• Its viscosity is higher than that of oxygen-rich blood. This is due to an increase in the size of red blood cells due to the intake of carbon dioxide in them.
• It has a higher temperature and a lower pH.
• Blood flows slowly through the veins. 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 as a whole makes up about two-thirds of the total volume.
• Due to the location of the veins, it flows close to the surface.

Compound

Laboratory studies make it easy to distinguish venous blood from arterial blood in composition.

• In the venous, the oxygen tension is normally 38-42 mm Hg (in the arterial - from 80 to 100).
• Carbon dioxide - about 60 mm Hg. Art. (in the arterial - about 35).
• The pH level remains 7.35 (arterial - 7.4).

Functions

The veins carry out the outflow of blood, which carries metabolic products and carbon dioxide. It receives nutrients that are absorbed by the walls of the digestive tract, and hormones produced by the endocrine glands.

Movement through the veins

Venous blood, in its movement, overcomes gravity and experiences hydrostatic pressure, therefore, when a vein is damaged, it flows calmly in a stream, and when an artery is damaged, it spurts.

Its speed is much less than that of the arterial. The heart ejects arterial blood at a pressure of 120 mm Hg, and after it passes through the capillaries and becomes venous, the pressure gradually drops and reaches 10 mm Hg. pillar.

Why is material taken from a vein for analysis?

Venous blood contains decay products formed during metabolism. In diseases, substances enter it that should not be in the normal state. Their presence makes it possible 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 in a fountain.

Venous bleeding is easier to stop, in some cases, when a blood clot forms, it may stop on its own. A pressure bandage applied 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, blood loss is significant, and death can occur within an hour.

Conclusion

The circulatory system is closed, so the blood in the course of its movement becomes either arterial or venous. Enriched with oxygen, when passing through the capillary system, it gives it to the tissues, takes away decay products and carbon dioxide, and thus becomes venous. After that, it rushes to the lungs, where it loses carbon dioxide and metabolic products and is enriched with oxygen and nutrients, becoming arterial again.

Female red, vital fluid that circulates in the animal body, in the veins, by the power of the heart. The blood consists of light, yellowish sap and tough liver; scarlet, vein, arterial blood circulates in combat veins; black, subcutaneous, venous ... Dahl's Explanatory Dictionary

Exist., f., use. very often Morphology: (no) what? blood for what? blood, (see) what? blood what? blood, what? about blood and on blood 1. Blood is a red liquid that moves through the blood vessels in your body and nourishes your body ... ... Dictionary of Dmitriev

And, suggestion about blood, in blood, kind. pl. blood, w. 1. Liquid tissue that moves through the blood vessels of the body and provides nutrition to its cells and metabolism in it. Deoxygenated blood. arterial blood. □ [Semyon] stabbed himself in the left… … Small Academic Dictionary

blood- and, suggestion; about the blood / vi, in the blood /; pl. genus. blood / th; and. see also krovushka, bloody, bloody 1) A fluid that moves through the blood vessels of the body and provides nutrition to its cells and metabolism in it. Deoxygenated blood … Dictionary of many expressions

BLOOD- BLOOD, a fluid that fills the arteries, veins and capillaries of the body and consists of a transparent pale yellowish. the color of the plasma and the shaped elements suspended in it: red blood cells, or erythrocytes, white, or leukocytes, and blood plaques, or ... Big Medical Encyclopedia

ICD 10 I95.95. ICD 9 458458 DiseasesDB ... Wikipedia

And suggest. about blood, in blood; pl. genus. blood; and. 1. A fluid that moves through the blood vessels of the body and provides nutrition to its cells and metabolism in it. Venous to. Arterial to. To. went from a nose. Break in k., to the blood. TO.… … encyclopedic Dictionary

blood- scarlet (Bashkin, Gippius, Meln. Pechersky, Sologub, Surikov, etc.); crimson (Turgenev); hot (Meln. Pechersky); hot (Sologub); hammered (Druzhinin); cherished (Gippius); sultry (Dravert); ebullient (Minaev) Epithets of literary Russian speech ... Dictionary of epithets

I (sanguis) is a liquid tissue that transports chemicals (including oxygen) in the body, due to which the integration of biochemical processes occurring in various cells and intercellular spaces into a single system occurs ... Medical Encyclopedia

- (sanguis, αϊμα) K. has long been known to people as a more or less brightly scarlet liquid that fills the body of warm-blooded and cold-blooded animals. Only in the 17th century were finally discovered those shaped elements of K., the presence of which ... ... Encyclopedic Dictionary F.A. Brockhaus and I.A. Efron