The basis of the life of any human body, as well as a unique transportation system located in his or her body - is the lifeblood. Responding to a question, how much blood is in the human body, it is necessary to take into account that the mass of blood is an average of six to eight percent of the total mass of the human body, and hence in the body of an adult weighing about 80 kilograms may be up to 5.5 liters of blood. Critical values of blood loss start with 500 milligrams and up to half of all - it all depends on endurance and other parameters of the human body.

The circulatory system of man is unique - it carries nutrients so that they come to each of the many billions of cells in our body, removing wastes and helping the body to store and regulate the temperature.

Blood consists of plasma - a colorless liquid, and the red color of her dyed red blood cells, which are located in the plasma. Number of liters of blood in a person - not the most important parameter of quality of life in many ways the level of health depends on the number of blood cells.

Interestingly, the residents of mountainous areas may be in the blood at fifty percent more red blood cells than people in big cities.

It's no secret that all there are four blood groups. They were discovered in the early 20 th century Austrian scientist Karl Landsteiner, in that in 1930 he was awarded the Nobel Prize in Physiology or Medicine. And in 1940, Landsteiner, together with other scientists Wiener and Levine opened the "Rh factor".

Belonging to a particular blood group does not change throughout life. Although science knows one fact of change of blood. This case originated with an Australian girl, Demi-Lee Brennan. After a liver transplant her Rh factor changed from negative to positive. This event excited the public, including doctors and scientists.
There are several divisions of the human blood groups, but most important is the separation of blood into four groups on the system "AB 0" and on two groups - under the "Rhesus". Four blood groups are denoted by symbols: I (0), II (A), III (B), IV (AB).Thus, blood group I (0) is the most common - it occurs in 45% of people on Earth. II (A) blood group predominates among the Europeans - with its carriers are about 35% of the people. III (B) blood group is less numerous - it can be found only in 13% of the people. The most rare blood type is IV (AB) - found only in 7% of the people.

The Japanese believe that the owners of I blood group - the people sociable, emotional and energetic. II People with blood group more stress, patience, love harmony and order, but a few stubborn. Impressionable, demanding, overbearing and creative individuals are people with blood type III. People with a rare group IV in life are guided by feelings, balanced, indecisive and cutting.