Blood - fast factsBernice Clark ▼ |
Just one drop of blood contains 15 millions of thrombocytes which promote blood clotting, 400 thousands of leucocytes which defend us from infections and up to 250 millions of red blood cells that carry oxygen around the body and take care to remove carbon dioxide and other waste. Our body contains around 4-6 litres of blood. Blood cannot be manufactured. If someone needs it, she will depend on a gift of good people - donated blood.
The idea of successful human to human transfusion puzzled doctors for centuries. In the long history of blood transfusion the most important year is 1901. That year Karl Landsteiner, an Austrian doctor and the most important individual in the field of blood transfusion, documented the first three human blood groups: A, B and O. In 1902, just the year later, two Italians, A. Decastrello and A. Sturli found AB, a fourth main blood group.
Which blood group of those four we have depends of the genes we inherited from our parents and it is typed according to the 30 protein and sugar compounds on the surface of the red blood cells. Our red blood cells also have another protein, so called Rh factor. If this antigen is present our blood group will be Rh positive and if the antigen is absent it will be negative. That means that you can be one of eight blood types: A positive, A RhD negative, B positive, B RhD negative, O positive, O RhD negative, AB positive and AB RhD negative.
The different substances in our blood work like chemical passwords. They help us distinguish our own cells from invading cells we ought to destroy. That's how group A has A antigens in the red blood cells and anti-B antibodies in its plasma. Group B has B antigens and anti-A antibodies in its plasma. Group O has no antigens, but both anti-A and anti-B antibodies. Group AB has both A and B antigens, but no antibodies.
A RhD-negative patient can receive A- or O- blood type. A RhD-positive patient can receive A-, A+, O- or 0+. Blood group A must never be given to a group B patient. B- can receive blood types B- or 0-. The patient with B+ blood type can receive blood types B+, B-, O+ or 0-. Patient with AB- blood type can receive blood types AB-, B-, A- or 0-. A patient with AB+ blood can receive blood from any donor. A patient with blood type O+ can receive blood types 0+ or 0-, while 0- can receive only 0- blood type. All that means that giving blood from the wrong ABO group to someone could be fatal.
About 21 percent of human population has blood group A, with the most higher frequencies in Australia, Scandinavia and Alaska, while in Central and South America there is no blood group A. B is a rare blood group with only 16 percent of population with it. The highest frequency of this group can be found in Central Asia and the lowest in both Americas and Australia.
The most common blood group around the world is O: about 63 percent of people share this group. Almost 100 percent of people in Central and South America has blood group O, while in Eastern Europe and Central Asia there is almost no blood group 0. The highest frequency of blood group AB can be found in Turkey, Finland and Hong Kong, and the lowest in Australia, Ireland and New Zealand.
Although there is no scientific arguments whatsoever that blood group may define someone's character, Japanese researchers tried to connect exactly those two. And what the results they have got? According to the data, representatives of blood group A have provocative and strong character, they are good organizers and a little bit suspicious. People who have blood group B are reasonable, like to change their opinion, they are fair players, open-minded and tolerant. Representatives of group O are skilled, creative, eager to stand out, jolly and passionate. People who have AB group have peculiar character; they are sentimental, stubborn and premeditated. ■