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

Only under the influence of enzymes. Hemoglobin helps transport oxygen from the lungs to various organs and tissues. The difference in the color of blood is explained by the unequal oxygen content in its cells. One type of blood vessel is the artery. They carry blood from the lungs and heart to other organs and tissues. This blood is saturated with hemoglobin, which in turn combines with hemoglobin, giving the blood a bright red color. Arterial blood is distributed through capillaries and small blood vessels with thin walls that carry oxygen and nutrients to all other cells of the body. The metabolic product produced by the cells is carbon dioxide. It enters the blood through the walls of the capillaries. From the capillaries, this rich blood flows into the veins, which are another type of blood vessel. Through veins, blood travels to the lungs and heart. The dark red, almost burgundy color of blood is due to the fact that there is no oxygen in it. In addition, red blood cells increase 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 the carbon dioxide is released into the air. After this, the person takes a breath, the blood is again saturated with oxygen, and the process begins all over again.

Some diseases can manifest not only as poor health, but also as various rashes on the body or changes in skin color. 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 penetrated by many capillaries through which blood flows. As a result of the tiny vessel rupturing, blood leaks out. Due to the process of releasing the body from leaked blood, dark circles appear. The composition of the blood includes, during the oxidation process it breaks down into smaller components and acquires a purple or color. The same process is observed after a blow or bruise.

Causes of dark circles under the eyes

An allergic reaction can cause black circles to appear under the eyes. When your eyes are watery, you can't resist scratching them. Due to constant rubbing, damage to the capillaries occurs, which entails the following.

It happens that fatigue, lack of sleep, and overexertion can change your appearance accordingly. But this lifestyle does not cause the appearance of black circles, it only makes the skin pale, which further emphasizes the blackness under the eyes. But poor nutrition, lack of vitamins and lack of rest together can negatively affect the skin around the eyes.

When talking to, you always look into his eyes. Noticing black circles on your interlocutor changes your impression of him. One gets the feeling that he is sick with something. This may be true. Impaired kidney function, cardiovascular diseases, and lack of oxygen can affect the color of the skin around the eyes. To correct this, cosmetic procedures will not help, the disease must be cured.

If you find black spots under your eyes, you should consult a doctor to determine the cause. This may be the first sign of a serious illness.

The culprit may be old age, which spares no one. The skin becomes thinner and 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 blood deficiency.

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

People who work a lot at the computer need to especially carefully monitor their vision, eyes and the condition of their skin. 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 medical attention immediately.

The main causes of bleeding are the inflammatory process or neoplasm on the walls of blood vessels, resulting from mechanical damage or disease. It can also be caused by a violation of the integrity of the vessel wall caused by poisoning, infection or lack of vitamins. If we are talking about the causes of bleeding from, then this may be increased blood pressure, injury, infectious and respiratory diseases. People often suffer from nosebleeds due to sudden changes in atmospheric pressure, overheating, or 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 caused by an ulcer of the digestive organs. In addition, bleeding from the rectum can be caused by a complicated diverticulum, cancer of the colon or cecum, and chronic hemorrhoids. However, bleeding from the rectum is not always so dangerous; sometimes it can be caused by cracks in the anal area or provoked by scratching in this area. Whatever the location of the bleeding, it is necessary to take into account the force with which it flows and what it is. If there is bleeding from the anus, it is necessary to report other disturbing symptoms, for example, changes in stool, pain, etc. The presence of internal bleeding, the cause of which may be a bruise 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. Signs of this condition include pallor of the skin and mucous membranes, general weakness, rapid, weakly audible pulse and low blood pressure. If we talk about uterine bleeding, there are many reasons for it. They can be caused by inflammation of the reproductive organs, disruption of the endocrine system, intoxication of the body, and even severe neuropsychic stress. Uterine bleeding can also be triggered by lack of rest during work, the presence of polyps and neoplasms of the uterus, and the use of certain medications.

Sources:

• Bleeding

Blood constantly circulates throughout the body, providing transport of various substances. It consists of plasma and a 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, rich in platelets, and if damaged, venous bleeding is easier to stop.
2. The pressure in the veins is lower, so if a vessel is damaged, the amount of blood loss is lower.
3. Its temperature is higher, so it additionally prevents rapid heat loss 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, blood moves through them in spurts.

Arterial and venous blood do not mix in the heart. The first passes along the left side of the heart, the second - along the right. They are mixed only in case of serious heart pathologies, 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. It is then distributed throughout the body through arteries and capillaries, carrying oxygen and nutrients.

The aorta is the largest artery, which is then divided into superior and inferior. Each of them supplies blood to the upper and lower parts of the body, respectively. Since the arterial system “flows around” absolutely all organs and is supplied to them with the help of a branched system of capillaries, this circle of blood circulation is called large. But the arterial volume is about 1/3 of the total.

Blood flows through the pulmonary circulation, which has given up all the oxygen and “taken away” metabolic products from the organs. It flows through the veins. The pressure in them is lower, the blood flows evenly. It returns through the veins 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 speed of blood flow in order to deliver oxygen to the organs as quickly as possible. The walls of the veins are thinner and more elastic. This is due to the lower speed of blood flow, as well as the large volume (venous is about 2/3 of the total volume).

What kind of blood is in the pulmonary vein?

The pulmonary arteries ensure the flow of oxygenated blood into the aorta and its further circulation throughout the systemic circulation. The pulmonary vein returns some of the oxygenated blood to the heart to nourish the heart muscle. It is called a vein because it supplies blood to the heart.

What is venous blood rich in?

When the blood reaches the organs, it 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.

Its saturation and density depend on the vessels through which venous blood flows. The closer to the heart, the thicker it is.

Why are tests taken from a vein?

This is due to the type of blood in the veins - saturated with metabolic products and vital functions of organs. If a person is sick, it contains certain groups of substances, remains of bacteria and other pathogenic cells. In a healthy person, these impurities are not detected. By the nature of the impurities, as well as by the level of concentration of carbon dioxide and other gases, the nature of the pathogenic process can be determined.

The second reason is that venous bleeding when a vessel is punctured 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 minor injury can be very dangerous for a person.

How to distinguish venous bleeding from arterial bleeding:

1. Assess the volume and nature of leaking blood. The venous flows out in a uniform stream, the arterial flows out in portions and even in “fountains”.
2. Determine 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 venous clot faster?

It is thicker and contains a large number of platelets. The low speed of blood flow allows the formation of a fibrin mesh at the site of vessel damage, to which platelets “cling.”

How to stop venous bleeding?

With minor damage to the veins of the extremities, it is often 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 placed above the damaged vein to limit the amount of blood flowing to the injury site. In summer you can keep it for about 2 hours, in winter - for an hour, maximum one and a half. During this time, you need to have time to deliver the victim to the hospital. If you hold the tourniquet longer than the specified time, tissue nutrition will be disrupted, which threatens necrosis.

It is advisable to apply ice to the area around the wound. This will help slow down your blood circulation.

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There's so much you can't find on the net. Even the question about the color of blood and veins is often accompanied by assumptions and fiction, although most people actually know the answer. Yes, everything is simple here - the blood is red, only in different shades, depending on the amount of hemoglobin in it and oxygen enrichment. Everything is as taught in biology and BJD at school: arterial blood(oxygen-rich, coming from the heart) bright scarlet color, A venous(giving oxygen to the organs, returning to the heart) – dark red(burgundy). The veins that are visible under the skin are also red when blood flows 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 this depend on?” and “Why are veins blue or cyan?”

The red color of blood can have different shades. Oxygen carriers, i.e. red blood cells (erythrocytes), are a shade of red depending on hemoglobin, an iron-containing protein found in them that can bind with oxygen and carbon dioxide to carry them to the desired location. The more oxygen molecules connected to hemoglobin, the brighter the red color the blood is. That’s why 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, the blood contains other cells besides red blood cells. These are also leukocytes (white blood cells) and platelets. But they are not in such significant quantities compared to red blood cells as 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 not at all blue in color. They are red, like the color of the blood that flows through them. And you shouldn’t believe in the theory that you can find on the Internet that the blood actually runs through the vessels is blue, but when cut and in contact with air it instantly turns 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 explained by the laws of physics about the reflection of light and our perception. When a beam of light hits the body, the skin reflects some of all the waves and therefore looks light, well, or different, depending on melanin. But it transmits the blue spectrum worse than red. 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 gives us red. But, interestingly, the vein actually reflects even a little more red than the skin in the blue spectrum of light. But why then do we see veins blue or cyan? And the reason, in fact, lies in our perception - the brain compares the color of the blood vessel against the bright and warm tone of the skin, and in the end shows us blue.

Why don’t we see other vessels through which blood flows?

If a blood vessel is located closer than 0.5 mm to the surface of the skin, then it generally absorbs almost all blue light, and reflects 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 veins that 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 blood volume is permanently in the veins, which means they are larger than other vessels. In addition, arteries have much thicker walls than veins, because they have to withstand greater 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 color are veins actually?

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 aristocrats, the expression “blue bloods” arose due to the paleness of their skin. Until the twentieth century, tanning was not in fashion, and the aristocrats themselves, especially women, hid from the sun, which protected their skin from premature aging and looked appropriate for their status, that is, they differed from the serfs who “plowed” all day in the sun. We now understand that pale skin color with a blue tint is actually a sign of less 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 the Latin cyanea - blue). The reason for this is not the same hemoglobin. Their protein contains more copper than iron, which during oxidation acquires a blue tint instead of the red we are accustomed to. These people are considered more resistant to many diseases and even injuries, as their blood is said to clot several times faster and are not susceptible to many infections. In addition, there are different theories about the origin of kianeticians, including that they are descendants of aliens. There is not much information about them on the Internet, but there are articles in foreign publications where the birth of such children is explained by the abuse of rudimentary drugs long before conception. As they say, “Don’t smoke, girl, the children will be green!”, but the results from birth control may turn out blue (meaning the color of blood).

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 the interventricular septum, venous blood, which is located 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 largest artery (aorta) to the ventricle, and from the ventricle to 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.

Next, the venous blood flows through the pulmonary arteries into 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 to the functions it performs.

• 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.
• It has a higher temperature and lower pH level.
• 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. It contains nutrients that are absorbed by the walls of the 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. When diseases occur, substances enter it that should not be present in a normal state. 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.

Women red, vital fluid that circulates in the animal body, in the veins, by the power of the heart. The blood consists of light, yellowish fluid and thick liver; scarlet, veiny, arterial blood circulates in the fighting veins; black, subcutaneous, venous... Dahl's Explanatory Dictionary

Noun, g., used. very often Morphology: (no) what? blood, what? blood, (see) what? blood, what? blood, about 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... ... Dmitriev's Explanatory Dictionary

And, prev. 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, sentence; about blood/vi, in blood/; pl. genus. blood; and. see also blood, bloody, bloody 1) Liquid 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 liquid that fills the arteries, veins and capillaries of the body and consists of a transparent pale yellowish color. the color of plasma and the formed elements suspended in it: red blood cells, or erythrocytes, white, or leukocytes, and blood plaques, or ... Great Medical Encyclopedia

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

And, offer. about blood, in blood; pl. genus. blood; and. 1. Liquid that moves through the blood vessels of the body and provides nutrition to its cells and metabolism in it. Venous k. Arterial k. K. came out of the nose. To crash into a cell, until there is 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); seething (Minaev) Epithets of literary Russian speech... Dictionary of epithets

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

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