June 14 is World Donor Day, timed to coincide with the birthday of Karl Landsteiner, an Austrian scientist who first divided blood into groups.
The body of an adult contains an average of 6-8% of the total mass of blood. True, the average amount of blood in a child's body is slightly higher and amounts to 8-9%. Blood moves through the human body at different speeds. It flows fastest through the arteries - 1.8 km per hour. The average blood volume in an adult man is 5000-6000 ml.
74-year-old Australian James Harrison donated blood nearly 1, 000 times in his life. Antibodies in his rare blood group help newborns with severe anemia survive. In total, thanks to the donation of Harrison, according to rough estimates, more than 2 million babies were saved.
The loss of a quarter of the volume of blood from the vessels poses a threat to life. If a large vessel is damaged, death occurs faster, but not from blood loss, but from an instant drop in blood pressure and anoxia of the brain and myocardium.
A person can function normally if blood flows through the vessels not in jerks, but in a continuous flow. This was proved by the doctors of the American Craig Lewis, who was dying of heart disease - even an electronic pacemaker could not save his life. As a result, the patient's heart was removed, but connected to a different type of device that helps blood to circulate continuously throughout his body. Lewis lived five weeks literally without a pulse, and his EKG had a straight line all this time. The cause of his death was liver failure due to amyloidosis, which was not associated with the implanted apparatus.
It is believed that women, on average, are much less afraid of blood than men. This is due to the fact that women have to see their menstrual blood regularly.
Our blood is red because it is full of red blood cells - red blood cells. The red color is given to them by iron, which is part of hemoglobin. Red blood cells help to exchange gas between tissues. The life of these cells lasts about 120 days, after which they are destroyed in the liver and spleen.
The protective function of the blood is helped by leukocytes, or white blood cells. They play a major role in the specific and nonspecific protection of the body from external and internal pathogenic agents, as well as in the implementation of typical pathological processes. The lifespan of these cells ranges from several days to several years.
Another guests of our blood are platelets, or colorless little bodies. These cells are responsible for blood clotting. They live in the body for only 8-10 days.
New blood cells are produced by the bone marrow. This unique organ weighs on average about two and a half kilograms and manages to produce about a ton of leukocytes and 650 kilograms of red blood cells in 70 years of life.
An adult's heart pumps about 10 thousand liters of blood per day! One beat of the heart pushes about 130 milligrams of blood into the artery. And the total length of blood vessels in the human body is about 100, 000 km.
There are several divisions of human blood into groups, but the most important is the division of blood into four groups according to the "AB0" system and into two groups - according to the "Rh" system. The four blood groups are designated by symbols: I (0), II (A), III (B), IV (AB). So, blood group I (0) is the most common - it is found in 45% of people on Earth. II (A) blood group prevails among Europeans - about 35% of people are carriers. III (B) blood group is less numerous - it can be found in only 13% of people. The rarest blood group is IV (AB) - found in only 7% of people.
People with blood group 1 are universal donors, and people with blood group 4 are universal recipients.
Hemophilia, or poor blood clotting, is a disease that has been called "royal" or "Victorian". Due to incestuous marriages between European rulers, it spread to many royal houses. The most famous carrier of hemophilia in history was Queen Victoria, who started it centuries ago.
Blood groups are unevenly distributed among different nationalities and races. So, 80% of Indians have I blood group, III prevails among Asians, and II among the inhabitants of northern Europe.
A blood stain can be used to identify a criminal in the same way as with fingerprints.
Some species of toad-like lizards, in extreme danger from a predator, use a unique defense mechanism: they shoot their blood from the corners of their eyes at a distance of up to one and a half meters.
Icefish, or whitefish, live in Antarctic waters. This is the only vertebrate species that does not have erythrocytes and hemoglobin in their blood, which is why the blood of ice fish is colorless. Their metabolism is based only on oxygen dissolved directly in the blood. This structure of the circulatory system allowed white bloodworms to exist in a habitat with temperatures below the freezing point of water.