Although Valentine's Day has led us to believe completely different information, our heart actually has a dull Brown color. Why is blood red? Let's find out the real reason.
The most pressing question for many
There are many organs in our body that have the most different colors. For example, we have bright pink lungs, a brown liver and a gray brain. And by the way, red blood flows through your veins and arteries. Each of us has probably wondered more than once why blood is red. We have the answers for you.
What is blood really?
Human blood is not just a liquid. It contains a lot of different elements that spread nutrients throughout the body and fill our tissues with oxygen. Most of our blood consists of plasma, in which blood cells (formed elements) are suspended, and any substances that are carried (besides oxygen) dissolve here. Plasma is the most important component of this important liquid and is very pale in color with a yellow tint. But as soon as the formed elements dissolve in it, it sharply changes its color and becomes slightly cloudy. The most common type of blood cell found in plasma is red blood cells, which contain a protein called hemoglobin.
What is the truth about the color of blood?
The generally accepted opinion is that it is iron, which can be found in hemoglobin, that gives our blood this red color, but everyone who believes so is very much mistaken. The red color is formed due to heme, a special pigment that is part of hemoglobin and contains iron ions. Oxygen, in turn, combines with iron, and it is this interaction that makes our blood red. The other components of a blood cell do not affect its color in any way.
Light or dark?
If hemoglobin contains high level oxygen, then it will reflect certain wave lines of light, absorbing all others, and thereby give the blood a bright red color. If it contains less oxygen, the reflected waves will be slightly different, the blood will become slightly darker.
What about blue blood?
As for people of aristocratic origin, the so-called blue-blooded individuals, they have almost the same red liquid as everyone else. But with hypoxia (dangerous low level oxygen in the blood) the wavelengths of reflected light reach the violet hue at the end of the spectrum. And then you can see blue veins through the skin.
Surely every person has asked the question: “Why is blood red?” To get the answer, you need to consider what it consists of.
Compound
Blood is a rapidly renewing connective tissue, which circulates throughout the body and carries gases and substances necessary for metabolism. It consists of a liquid part, called plasma, and formed elements - blood cells. Normally, plasma makes up about 55% of the total volume, cells – about 45%.
Plasma
This pale yellow liquid performs very important functions. Thanks to plasma, cells suspended in it can move. It consists of 90% water, the remaining 10% are organic and inorganic components. Plasma contains microelements, vitamins, and intermediate metabolic elements.
Cages
There are three types of shaped elements:
- leukocytes are white cells that perform protective function, protecting the body from internal diseases and foreign agents penetrating from the outside;
- platelets - small colorless plates responsible for coagulation;
- Red blood cells are the same cells that make blood red.
Red blood cells give blood its red color
These cells, called red blood cells, make up most of the formed elements - more than 90%. Their main function is to transfer oxygen from the lungs to peripheral tissues and carbon dioxide from tissues to the lungs for further removal from the body. Red blood cells are continuously produced in bone marrow. Their lifespan is about four months, after which they are destroyed in the spleen and liver.
The red color of red blood cells is given by the protein hemoglobin found in them, which is capable of reversibly binding to oxygen molecules and transporting them to tissues.
The color of blood varies depending on whether it flows from the heart or to the heart. The blood that comes from the lungs and then travels through the arteries to the organs is saturated with oxygen and has a bright scarlet color. The fact is that hemoglobin in the lungs binds oxygen molecules and turns into oxyhemoglobin, which has a light red color. Upon entering the organs, oxyhemoglobin releases O₂ and turns back into hemoglobin. In peripheral tissues, it binds carbon dioxide, takes the form of carbohemoglobin and darkens. Therefore, the blood flowing through the veins from the tissues to the heart and lungs is dark, with a bluish tint.
An immature red blood cell contains little hemoglobin, so at first it is blue, then becomes gray, and only when ripe it becomes red.
Hemoglobin
This is a complex protein that includes a pigment group. One third of the red blood cell consists of hemoglobin, which makes the cell red.
Hemoglobin consists of a protein - globin, and a non-protein pigment - heme, containing ferrous ion. Each hemoglobin molecule includes four hemes, which account for 4% of the total mass of the molecule, while globin accounts for 96% of the mass. the main role in the activity of hemoglobin belongs to the iron ion. To transport oxygen, heme reversibly binds to the O₂ molecule. Ferrous oxide is what gives blood its red color.
Instead of a conclusion
The blood of humans and other vertebrates is red due to the iron-containing protein hemoglobin.. But there are living beings on Earth whose blood contains other types of protein, and therefore its color is different. In scorpions, spiders, octopuses, crayfish it is blue because it contains the protein hemocyanin, which includes copper, which is responsible for the hue. In sea worms, the blood protein contains ferrous iron, which is why it is green.
Blood is a combination of many substances - plasma and formed elements. Each element has strictly defined functions and tasks; certain particles also have a pronounced pigment, which determines the blood color. Why is human blood red? The pigment is contained in red hemoglobin; it is part of the red blood cell. It is for this reason that there are organisms on Earth (scorpions, spiders, monkfish) whose blood color is blue or green. Their hemoglobin is dominated by copper or iron, which gives the characteristic color of the blood.
To understand all these elements, it is necessary to understand.
Compound
Plasma
As already indicated, one of them is plasma. It takes up about half of the blood composition. Blood plasma turns blood into a liquid state, has a light yellow color and is slightly denser in properties than water. The density of plasma is provided by the substances dissolved in it: salts, fats, carbohydrates and other elements.
Shaped elements
Another component of blood is the formed elements (cells). They are represented by red blood cells blood bodies, - white blood cells, platelets - blood platelets. It is red blood cells that answer the question why blood is red.
At the same time circulatory system about 35 billion red blood cells move around. Appearing in the bone marrow, hemoglobin is formed - this is a red pigment, saturated with protein and iron. The task of hemoglobin is to deliver oxygen to vital parts of the body and remove carbon dioxide. Red blood cells live on average 4 months, then they disintegrate in the spleen. The process of formation and breakdown of red blood cells is continuous.
Hemoglobin
The blood, enriched with oxygen in the lungs, disperses to the vital organs of the body. At this moment it has a bright scarlet color. This occurs due to bonding with oxygen, resulting in oxyhemoglobin. As it passes through the body, it distributes oxygen and becomes hemoglobin again. Next, hemoglobin absorbs carbon dioxide from tissues and is transformed into carbohemoglobin. At this moment, the color of the blood changes to dark red. Immature red blood cells also have a bluish tint; as they grow, they then become colored grey colour and then turn red.
The color of the blood may vary. Answers to the questions why blood is dark red or bright red. Different shade A person's blood receives depending on whether it moves towards the heart or away from it.
Very often people wonder why veins are blue and blood is red? The fact is that venous blood is the blood that flows through the veins to the heart. This blood is saturated with carbon dioxide and deprived of oxygen, has lower acidity, contains less glucose and significantly more final metabolic products. In addition to being dark red, venous blood also has a bluish, blue tint. However, not so strong as to “stain” the veins blue.
Why is blood red? It's all about the process of passing light rays and the ability of bodies to reflect or absorb solar rays. The beam must pass through the skin to reach venous blood, fat layer, the vein itself. Sunbeam consists of 7 colors, three of which blood reflects (red, blue, yellow), the remaining colors are absorbed. Reflected rays pass through tissues a second time to enter the eye. At this moment, red rays and low-frequency light will be absorbed by the body, and blue light will be transmitted. We hope that we have answered why a person has dark red and bright red blood.
Does blood have to be red? Why shouldn’t it, for example, be green or blue, or, in general, like in the movie “Predator,” glow in the dark? Do you remember the colorless blood-acid in Alien? Or the “blue blood” of Russian nobles? Isn't it cool? So, let's try to figure out what causes the color of blood:
All people have red blood. As you know, it gives color hemoglobin, which is the main component of the red blood cell, filling it by 1/3. It is formed as a result of the interaction of the globin protein with four iron atoms and a number of other elements. It is thanks to iron oxide (Fe 2+) that hemoglobin acquires red color. All vertebrates, some species of insects and mollusks have iron oxide in their blood protein, and therefore their blood has a scarlet color.
But it turns out that blood doesn’t have to be red at all. Some animals have blood of a completely different color. For example, in some invertebrates, oxygen is carried not by hemoglobin, but by another iron-containing protein - hemerythrin or chlorocruorin.
Hemerythrin, which is a respiratory pigment in the blood of brachiopods, contains five times more iron than hemoglobin. Oxygenated hemerythrin gives blood violet tint, and having given oxygen to the tissues, such blood becomes pink. Hemerythrin is localized in cells, which, unlike ordinary red blood cells, are called pink blood cells.
But in polychaete worms the respiratory pigment is another iron-containing protein - chlorocruorin, dissolved in blood plasma. Chlorocruorin is close to hemoglobin, but its basis is not oxide iron, but ferrous iron, which gives blood and tissue fluid green color.
However, nature is not limited to these options. The transfer of oxygen and carbon dioxide, it turns out, may well be carried out by respiratory pigments based on ions of other metals (besides iron).
For example, sea squirts have blood colorless, since it is based on - hemovanadium, containing vanadium ions.
Do you remember our nobles with blue blood? It turns out that this happens in nature, but the truth is only in octopuses, octopuses, spiders, crabs and scorpions. The reason for such a noble color lies in the fact that the respiratory pigment of their blood is not hemoglobin, but hemocyanin, in which copper (Cu 2+) is present instead of iron. Combining with atmospheric oxygen, hemocyanin turns blue, and, giving oxygen to tissues, it becomes somewhat discolored. As a result of this, these animals have blood flowing in their arteries. blue blood, and in the veins is blue. If hemoglobin is usually found in both plasma and shaped elements blood (most often in red blood cells), then hemocyanin is simply dissolved in the blood plasma. Interestingly, there are organisms, for example, some mollusks, which can simultaneously contain hemoglobin and hemocyanin, and in some cases one of them acts as an oxygen carrier in the blood, and the other in the tissues.
By the way, there are still known cases when people had blue blood. True, not at all among the nobles. The Trud newspaper once published about one such case (dated March 17, 1992):
“Mikheev, a resident of Severodvinsk, decided to donate blood for noble reasons, as well as to receive a discounted lunch coupon. He passed. The doctors looked at it and gasped: the blood turned out to be a strange bluish color. They sent it for analysis to the Arkhangelsk Toxicology Laboratory. It turned out that unusual color caused by functional changes in the liver. And these changes are associated with Mikheev’s habit of drinking alcohol-containing liquids of ignoble, let’s say, origin. For example... stain..." Who knows, maybe our blue-blooded kings didn't disdain stain either... ;-)
Well, and finally, a tablet where all this completely useless knowledge about the color of blood is brought together:
Blood color |
Where is it kept? |
Main element |
Representatives |
|
Red, scarlet |
Hemoglobin |
Red blood cells, plasma |
All vertebrates, some invertebrate species |
|
Violet
|
Hemerythrin |
Pink blood cells |
Brachiopods, sipunculids, priapculids |
|
Green |
Chlorocruorin |
Polychaete worms (polychaetes) |
||
Colorless |
Hemovanadium |
Sea squirts |
||
Blue |
Hemocyanin |
Many molluscs and arthropods |
P.S. By the way, why did I get interested in this stupid question about the color of blood... The fact is that last week I had fun with the fact that, together with kpblca wrote a semi-fiction story. The beginning, but the unfinished “story” itself. By the way, maybe there will be people willing to write a sequel to it...
Update (14-Jun-2003): The story would be incomplete if, having talked about red, green, blue, blue and violet blood, I did not mention the yellow and orange blood, which is often found in insects.
The reason that I forgot about this blood is that I was looking for information about respiratory pigments, and in insects the blood (or more precisely, the hemolymph) is devoid of these pigments and does not participate in the transfer of oxygen at all. Respiration in insects is carried out using tracheas - branching tubes that directly connect cells internal organs with the air environment. The air inside the tracheal tube is motionless. There is no forced ventilation, and the influx of oxygen into the body (as well as the outflow of carbon dioxide) occurs due to diffusion due to the difference in the partial pressures of these gases at the inner and outer ends of the tube.
This oxygen supply mechanism strictly limits the length of the tracheal tube, the maximum length of which is quite simply calculated, so the maximum size of the body of the insect itself (in cross-section) cannot exceed the size chicken egg. However, if there were higher pressure on our planet, insects could reach gigantic size(like in science fiction horror films).
The color of hemolymph in insects can be almost any color, because... it contains many different substances, including poisons and acids. Thus, the blister family got its name precisely because of the ability of its representatives (for example, the Spanish fly) to secrete drops from the joints of the thighs and legs yellow blood, which when it comes into contact with human skin causes burns and abscess-like watery blisters.
The hemolymph of representatives of many families contains very toxic substances, in particular cantharidin. If such poisonous hemolymph enters the mouth, it can cause serious poisoning and even death. The blood of ladybugs is especially poisonous - it has a specific smell, is cloudy, yellow-orange the liquid that they secrete in case of danger.
Science knows that different living organisms on the planet have different blood colors.
However, in humans it is red. Why is blood red? This question is asked by both children and adults.
The answer is quite simple: the red color is due to hemoglobin, which contains iron atoms in its structure.
What makes blood red is hemoglobin, which consists of:
- From a protein called globin;
- The non-protein element heme, which contains the ferrous ion.
It was possible to find out what gives the red color, but its elements turn out to be no less interesting. What elements give it this color is an equally interesting aspect.
Blood contains:
- Plasma. The liquid is light yellow in color, with its help the cells in its composition can move. It is composed of 90 percent water, with the remaining 10 percent made up of organic and inorganic components. Plasma also contains vitamins and microelements. The light yellow liquid contains many useful substances.
- The formed elements are blood cells. There are three types of cells: white blood cells, platelets and red blood cells. Each type of cell has certain functions and characteristics.
These are white cells that protect the human body. They protect him from internal diseases and foreign microorganisms penetrating from outside.
This is a white element in color. Its white hue is impossible not to notice during laboratory research, so such cells are determined quite simply.
White blood cells recognize foreign cells that can cause harm and destroy them.
These are very small colored plates whose main function- folding.
These cells are responsible for ensuring that the blood:
- It coagulated and did not flow out of the body;
- Coagulates quite quickly on the surface of the wound.
More than 90 percent of these cells are in the blood. It is also red because red blood cells have this hue.
They carry oxygen from the lungs to peripheral tissues and are continuously produced in the bone marrow. They live for about four months, then are destroyed in the liver and spleen.
It is very important for red blood cells to carry oxygen to various tissues of the human body.
Few people know that immature red blood cells are blue, then acquire a gray tint and only then become red.
There are quite a lot of human red blood cells, which is why oxygen reaches peripheral tissues so quickly.
It is difficult to say which element is more significant. Each of them has important function affecting human health.
Children often ask questions regarding the components of the human body. Blood is one of the most popular topics of discussion.
Explanations for children should be extremely simple, but at the same time informative. Blood contains many substances that differ in function.
Consists of plasma and special cells:
- Plasma is a liquid that contains useful substances. It has a light yellow tint.
- The formed elements are erythrocytes, leukocytes and platelets.
The presence of red cells - erythrocytes - explains its color. Red blood cells are red by nature, and their accumulation leads to the fact that a person’s blood is exactly this color.
There are about thirty-five billion red cells that move throughout the human body in the blood vessels.
Why are veins blue
The veins carry burgundy blood. They are red, like the color of the blood that flows through them, but not blue. The veins only appear blue.
This can be explained by the law of physics about the reflection of light and perception:
When a ray of light hits the body, the skin reflects some of the waves and looks light. However, it transmits the blue spectrum much worse.
The blood itself absorbs light of all wavelengths. Skin gives for visibility Blue colour, and the vein is red.
Human brain compares color blood vessel against warm skin tone, resulting in blue.
Blood of a different color in various living creatures
Not all living organisms have red blood.
The protein that gives this color in humans is hemoglobin, contained in hemoglobin. Other living beings have other fat-containing proteins instead of hemoglobin.
The most common shades besides red are:
- Blue. Crustaceans, spiders, mollusks, octopuses and squids boast this color. And blue blood has great value for these creatures, as it is filled important elements. Instead of hemoglobin, it contains hemocyanin, which contains copper.
- Violet. This color is found in marine invertebrates and some mollusks. Typically, such blood is not only purple, but also slightly pink. Color pink blood in young invertebrate organisms. IN in this case protein - hemerythrin.
- Green. Found in annelids and leeches. The protein is chlorocruorin, close to hemoglobin. However, iron in this case is not oxide, but ferrous.
The color of blood varies depending on the protein it contains. Whatever color the blood is, it has a huge amount useful substances necessary for a living organism. Pigment is important for every organism, despite its diversity.
Video - Secrets and mysteries of our blood
