Blood

As you know, the blood - is a unique biological fluid, having a wide variety of properties, and performs a huge number of functions ranging from transportation and finishing protective. Most of these properties and functions are common, ie common to all members of the human race, but some characteristics of the blood purely individual. Such was, for example, refers to a group of blood.

What is the blood group from which it depends and which has practical significance? Blood - is one of the genetic components of each person, which is inherent in the genetic apparatus and is transmitted from the parents. We all know that there are only four blood types. But what is determined? Why does one person the first group of blood, and another quarter? It turns out that everything depends on the structure of red blood cells, the same red blood corpuscles, which carry oxygen and cells derive carbon dioxide. Erythrocytes represent a bull of a spherical shape, but with repeated increases with an electron microscope is becoming apparent that the surface of red blood cells very often "littered" a wide variety of microstructures that each person has a different structure, shape, spatial location, etc. Without going into deep details, we note that these microstructures, known as antigens, many properties depend on red blood cells, including blood group. For antigens that define blood group coined the term complex "agglyutinogeny. Why? Soon find out ...

Total, there are two types agglyutinogenov: A and B. How can this be, because we do not have two groups of blood, but four? It is very simple. If a person has agglyutinogen A, then had a second group of blood, if B - third. Often, however, red blood cells do not have agglyutinogenov. In this case we speak about the first group of blood. Or, conversely, the same red blood cells are present both antigens. As you may have guessed, in this case it is about the fourth group.

Other mandatory components of each of the blood groups are special protein complexes - hemagglutinins, which are constantly circulating in the plasma. Thus, for the first group is characterized by the presence of blood α-and β-agglutinins, for second - only β, for the third - only α. Fourth group of blood does not contain agglutinins. Thus, antigenic characteristics of each blood group is as follows:

I - 0 (α, β);
II - A (β);
III - B (α);
IV - A, B (absent).
Supervisory reader drew attention to the fact that none of the blood groups do not occur with the same name and hemagglutinins agglyutinogeny (ie, A and B and α or β). Otherwise, they would have entered the agglutination reaction and glued to each other. That's where these erythrocyte antigens and plasma protein complexes is a specific name (agglutinate - connect, stick together). Glued red blood cells lose the ability to carry oxygen, and settle very quickly destroyed. The process of destruction of red blood cells is so fast that a person can die within minutes. Therefore blood transfusion or red cell mass in the first group determine the patient's blood, and then closely monitored his physical condition during the transfusion. The main problem with this is not allowed to hemagglutinins patient "met" with agglyutinogenami blood. More than anything in this regard, the "lucky" people with the fourth group of blood. Since their plasma, no agglutinins, they can pour the blood of any group. But patients with the first group can only pour the blood of the same group. But "pervogruppniki" can be donors for all blood groups.

Inheritance of blood group person gets one gene from his father, the second - from the mother, ie blood group is always represented by two genes. These genes and determine the antigenic structure of erythrocytes. And what kind of blood is obtained if one parent will inherit the gene of the first group (ie, "zero"), but on the other - the second group (ie A)? In this case, the child will be with the second group of blood, presented as A0. The situation is similar to the third group. But the pair with the first and the fourth group of children may be only the second (A0) or third (B0) blood group, but certainly not the first or the fourth. In this context, doctors know a lot of tragicomic stories, when the infuriated husband, who blamed his no innocent spouse in "treason," managed to calm down, just focusing on the mysteries of hereditary transmission of blood groups.