Blood performs many vital functions in our body. important functions. It is no coincidence that large blood loss, as well as poor circulation, can be disastrous for us. We suggest that you familiarize yourself with the list of functions that are “assigned” to blood:
- Transport function. Blood is “responsible” for transporting various substances. It is thanks to her that cells and internal organs receive oxygen and nutrients, the blood removes carbon dioxide and metabolic end products from them. In this regard, three subfunctions are distinguished: respiratory, trophic and excretory.
- Thermoregulatory function. Blood, in addition to oxygen and nutrients, transfers heat from more heated organs to less heated ones.
- Protective function. Implementation of non-specific and specific immunity: Blood clotting prevents blood loss during injury.
- Regulatory, or humoral function. This refers to the delivery of hormones, peptides, ions and other physiological active substances from the places of their synthesis to the cells of the body, which allows for the regulation of many physiological functions.
- Homeostatic function. Blood ensures the maintenance of a constant internal environment of the body (acid-base balance, water-electrolyte balance and other parameters).
Blood composition
The liquid component of blood can be distinguished - blood plasma and shaped elements blood. The formed elements are red blood cells, white blood cells and platelets. The share of formed elements accounts for 40–45%, the share of plasma – 55–60% of blood volume.
Blood plasma
From 90 to 92% of blood plasma is water, and the remaining 8–10% is dry residue, which consists of organic and inorganic substances. Plasma constantly contains all vitamins, microelements, as well as intermediate metabolic products.
Formed elements of blood
Red blood cells. They contain hemoglobin, which makes our blood red. Perform the following functions:
- respiratory;
- regulation of blood pH;
- nutritious;
- protective;
- participate in the process of blood clotting;
- are carriers of various enzymes and vitamins (B1, B2, B6, ascorbic acid);
- are carriers of group blood characteristics.
Leukocytes. They are also white blood cells - colorless cells ranging in size from 8 to 20 microns. Perform in the body protective function. White blood cells are produced in red bone marrow from a single stem cell.
Platelets, or blood platelets - flat cells of irregular round shape with a diameter of 2–5 microns. The main function of platelets is to participate in hemostasis (stopping bleeding in case of damage to the walls of blood vessels and maintaining the liquid state of the blood). Platelets “produce” and secrete a number of biologically active substances: serotonin, adrenaline, norepinephrine and substances called lamellar coagulation factors.
Hemoglobin and red color of blood
As already mentioned, it is hemoglobin that colors our blood red. It is also the basis of the red blood cell, filling it by 1/3. It is formed as a result of the interaction of a protein called globin with four heme molecules.
Heme, which contains a divalent iron atom that can attach or donate an oxygen molecule. In this case, the valence of iron, to which oxygen is attached, does not change.
It is thanks to this divalent iron oxide (Fe2+) that hemoglobin acquires its red color. All vertebrates, some species of insects and mollusks have iron oxide in their blood protein, and therefore their blood is red.
Blood of a different color
Red is not the only blood color possible in nature. And this is due to the fact that some living beings’ red blood cells contain not hemoglobin, but other iron-containing proteins. This is observed in some species of invertebrates, in particular mollusks.
Their blood contains the protein hemerythrin, which is a respiratory pigment in the blood and contains five times more iron than hemoglobin. Hemerythrin, saturated with oxygen, gives the blood a purple tint, and when it gives oxygen to the tissues, such blood becomes pink.
Another iron-containing protein - chlorocruorin - gives blood and tissue fluid green color. This protein is dissolved in the blood plasma and is close in composition to hemoglobin, but the iron in it is not oxide, as in the blood of mammals, but ferrous. That's why the color turns out green.
However, the color range of the blood of living beings is not limited to red, purple and green. For example, octopuses, octopuses, spiders, crabs and scorpions - blue bloods in the most literal sense. The reason is that in these animals and insects the respiratory pigment of the blood is not hemoglobin, but hemocyanin, which contains copper (Cu2+) instead of iron.
By the way, recently, as a result of one of the studies, a discovery was made regarding the ancient Egyptians, more precisely, the color of their blood: it is quite possible that they also had blue.
All babies have their blood taken for analysis immediately after birth. In the first hours of life, doctors check general blood counts and whether the little person has severe congenital pathologies, for example, hypothyroidism and phenylketonuria. It is important to identify these ailments as soon as possible, because the health of the baby directly depends on this, as well as his further intellectual and physical development in the future life.
What will the blood test show?
A blood test today is one of the best and most accessible indicators of changes occurring in the body. If a child feels unwell, most likely the doctor will recommend a test, which in a matter of hours will help identify, for example, inflammatory process and start treatment as soon as possible.
Infectious diseases in a newborn
This condition, dangerous to the life and health of the baby, is characterized by a sharp jump in the level of leukocytes and an increase in the erythrocyte sedimentation rate (ESR). The first changes can be detected in a child even before the appearance of external signs diseases, which is very important for more successful treatment.
Pediatricians recommend that parents do not avoid this simple study, although children usually do not like this process too much. In order to calm a child, you must first calm down yourself. And then talk to the baby and convince him that all this is not dangerous at all. In addition, after donating blood without tears, you can go to your favorite toy store or buy a delicious sweet at the nearest confectionery shop. Try it, this method works!
Why is blood red?
In addition, children aged why are very interested in learning more about the structure of the body. Therefore, to the question “why is blood red,” young mothers and fathers need to prepare a detailed answer in advance. It should be something like this:
Human blood consists of a large number of different cells. They are so small that we cannot see them without special equipment. There are red blood cells in the blood; doctors call them erythrocytes. They contain a special substance called hemoglobin. It, in turn, contains iron, which gives our blood its red color. In addition, hemoglobin is the main carrier of oxygen in the body!
photo: depositphotos.com, channel: Igor Koval
Blood forms the basis of the life of a living organism. Circulating through the system of blood vessels, veins and arteries, it transports oxygen and substances necessary for metabolism or resulting from it to various organs. metabolic processes.
But the functions of blood are not limited to transporting nutrients and metabolic products. Blood regulates body temperature and transports hormones responsible for vital processes; protects the body from infections and damage.
What is blood for: basic functions
Almost all processes in the body related to respiration and digestion are associated with blood supply. It is the blood that transports oxygen from the lungs to the tissues, and carbon dioxide from the tissues and organs to the lungs. The secretion products of endocrine glands - hormones - are transported throughout the body with the blood, and this ensures coordination between various organs.
Nutrients from small intestine Through capillaries, thanks to the blood, they travel from the digestive tract to the liver. This is where the modification happens fatty acids, glucose, amino acids and regulation of their quantity, depending on what the body needs for this moment to a greater extent. 
Further, the transported substances reach their “destination points” through tissue capillaries. End products enter the blood from tissues, which are then excreted from the body, for example, in urine.
In warm-blooded organisms, blood plays a primary role in the process of maintaining optimal body temperature, or thermoregulation. In different parts of the body, the absorption and release of heat must be balanced, and this balance is made possible precisely because the blood carries heat.
The main center of thermoregulatory processes is located in the brain - the hypothalamus, which is sensitive to changes in the temperature of the blood passing through it. The hypothalamus regulates the processes by which heat is released or absorbed.
For example, heat loss can be adjusted by changing the diameter blood vessels skin, which, in turn, changes the volume of blood flowing near the surface of the body (and this is where heat is lost most easily).
About the color of blood
Blood is a liquid, the fluidity of which is determined by its viscosity and the nature of the movement of its components. Blood viscosity depends on the number of red blood cells and proteins it contains, and affects the speed of blood movement and blood pressure.
Blood consists of pale yellow plasma, which contains three types of cellular elements: red blood cells (erythrocytes), white cells (leukocytes), and platelets (platelets). The total volume of blood in the body of an adult male is about five liters, with most of it being plasma and the rest mostly red blood cells. Red blood cells contain the pigment hemoglobin, which gives blood its red color.
Main function red blood cells transport oxygen, and hemoglobin plays a key role in this process. Hemoglobin is an organic pigment that contains a compound of porphyrin with iron (heme) and the protein globin.
It is known that the blood in the arteries and veins has different shades: venous blood is dark, arterial blood is bright scarlet. This happens because the arteries carry blood from the heart and lungs and are saturated with oxygen. And through the veins, blood from tissues and organs flows to the heart, the hemoglobin in this blood is almost devoid of oxygen, which is why it has dark color.
Can blood be a different color?
Of course it can. For example, the blood of octopuses, scorpions, crayfish, spiders are blue, because instead of hemoglobin it contains hemocyanin, and in it the metal is not iron, but copper. 
If iron colors human blood red, copper gives the blood of octopuses and other organisms a blue or blue tint. By the way, when octopus blood is saturated with oxygen, it darkens, and in the veins, on the contrary, it turns pale.
And in nature there are sea worms whose blood is green. It gets this color thanks to the ferrous iron it contains.
If appeared fair blood If you have your period, but previously your menstruation was of a different nature (color, consistency, smell), you should immediately visit a gynecologist. Often such discharge is a sign serious illness. You may need to consult a neurologist and endocrinologist.
In the absence of deviations, the color of the secreted fluid may be scarlet, dark red or brown in the first and last days (daub). It also contains inclusions of mucus, fragments of rejected endometrium
Menstruation should be without the presence of an unpleasant (fetid) odor, itching, burning, severe pain, . This is considered normal if menstruation began on time, no less than 21 days from the previous critical days, the blood does not clot, overall volume discharge on average does not exceed 80-100 ml for the entire period, and their duration ranges from 3 to 7 days.
If women of reproductive age have periods like water with blood throughout the entire period, then at the end of it it will be necessary to seek advice from a gynecologist. It is recommended to be examined using an ultrasound (transvaginal), video colposcope (extensive colposcopy), and donate blood to determine the level of hemoglobin and hormones.
In girls for a year or 2 years after menarche and in women during premenopause, the preservation of scarlet (light) color of menstrual blood is not a pathology. However, a doctor's examination is recommended to rule out diseases.
Light, not abundant bleeding 2-2.5 weeks after menstruation may be due to ovulation (when the egg is released, the hormonal levels change, the follicle membrane is damaged). May be implantation bleeding, when the embryo implants into the endometrial tissue, rupturing the vessels. Normally, such red discharge lasts from several hours to 3-5 days, which is why women perceive it either as menstruation or as a deviation.
Pathology during light menstruation
There are several reasons why the discharge remains bright red, pink or faintly colored (beige), or critical days appear ahead of schedule. These are endocrine, gynecological and venereal diseases, spontaneous abortions early stage pregnancy, trauma to the mucous membranes with an intrauterine device, the consequence of unsuccessful curettage, cancer.
Symptoms of pathological abnormalities:
- less than 3 weeks or more than 35 days have passed between menstruation;
- scanty or heavy periods or they last longer than 7 days;
- there are clots larger than 2-2.5 cm;
- systematic cycle failures;
- light remains throughout the entire period of critical days;
- unpleasant odor reminiscent of rotten fish;
- itching, dryness;
- body temperature is higher than normal;
- cutting or other pain in the area genitourinary organs, paths;
- scanty discharge becomes more abundant over time, without signs of completion;
- bleeding systematically resumes every few days.
If there is at least one symptom, a diagnosis should be carried out immediately to find the cause of the deviation. Gynecological examination is required even if the color of menstruation is normal (dark red, not bright), but there are other symptoms of pathology. Early diagnosis will avoid complications, one of which is iron deficiency anemia. 
Reasons for appearance light color blood:
- criminal abortion;
- miscarriage;
- bacterial infections acquired through sexual contact (STDs);
- damage to the mucous membranes or endometrium by a medical instrument;
- incorrectly selected hormonal drugs, including contraception;
- low hemoglobin level.
With the help of a gynecologist, laboratory and hardware diagnostics, it is easier to identify the causes that provoked bleeding or eliminate factors that contribute to its reoccurrence. For example, they select adequate hormonal contraception, remove the intrauterine device, eliminate the consequences of abortion, and use other treatment methods.
Bacterial vaginosis
The vaginal microflora of women contains lactobacilli, which maintain optimal acidity of the reproductive tract environment and suppress pathogenic infections streptococcus, coli, staphylococcus and other agents. If they are violated natural level a woman may develop gardnerellosis (synonyms: dysbiosis of the vaginal environment, bacterial vaginosis).
Usually, the number of lactobacilli changes due to excessive douching, the use of low-quality products for intimate hygiene, after sexual intercourse (unprotected sex) or drug treatment (by-effect drugs). Pathology does not apply to venereology.
Symptoms of the disease: rotten fish (the aroma intensifies after sex), light blood, a lot of mucus, itching. For diagnosis, additional smears are taken from which pathogenic microflora will be inoculated.
If vaginosis is confirmed, therapy is prescribed using antibacterial drugs and other drugs appropriate for the treatment of the specific stage of the disease. It is necessary to eliminate gardnerellosis to avoid inflammatory processes.
During menstruation, the blood may appear pink, bright red, or like slightly colored water (ichor). If a test confirmation of pregnancy has already been received (standard or hCG), then such menstruation is a sign spontaneous abortion. A situation like this requires medical supervision with possible hormonal adjustments to preserve the fetus.
However, there are often cases when menstrual cycle operates according to schedule throughout the first trimester and is light. A doctor's consultation is advisable.
Conclusion
A woman is recommended to undergo regular general routine medical examinations to protect yourself from complications various diseases. After all, light menstrual blood occurs when there is a malfunction thyroid gland(hormonal imbalances), due to overwork, chronic fatigue, poor nutrition (strict diets), diseases nervous system and for many other reasons.
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.
