We all know that the blood found in our body is very important (essential) fluid, because any living organism is like a dead without it. It is found in every human body. About 5 liters blood is found inside a human body. Only through the blood, different types of tissues and cells inside the body are able to get nutritive elements and oxygen. Without blood, it is impossible to nourish the entire body. The blood is red in appearance and salty in taste. It appears as red colored fluid (liquid), but when we see it with the help of microscope, lots of cells are visible in it. These cells are called RBCs (red blood cells). These are also to be divided into many cells. In the blood of a person, about 4-5 lacks RBCs per cubic mm is found. The red color of blood is due to hemoglobin present in it. Iron particles presents in this hemoglobin. If hemoglobin did not present in blood, it did not able to carry oxygen to different tissues and cells. It is only possible through hemoglobin, because the hemoglobin has ability to carry oxygen to lungs.
There are about 5000 to 9000 of WBCs per cubic mm inside the body. These cells act as protective. They destroy bacteria responsible for harmful substance and diseases in the body and protect the body from harmful effects.
The blood is found in veins and shiny red in appearance. The blood found inside heart and vessels are thick red colored. The arteries circulate pure blood in different organs and the veins collect impure blood from different organs. Lungs veins also present in the body which acts as supplying of blood from the lungs to the heart and these carry shiny red blood.
Coagulation of blood or clotting of blood-
It is very important incident (process) in which blood is clotted. Substance (protein) named fibrinogen also present in the blood which is responsible for blood clotting. As soon fibrinogen comes in contact of air as it makes the upper layer of blood hard resulting the blood is clotted. If these substances are absent in the blood, the blood will not be able to coagulate after coming in contact of air. For illustration- when a person gets injury (cut), bleeding starts from that part and is clotted in contact of air resulting a thick layer is appeared (formed) on the affected part and bleeding is stopped. On the other hand, if these substances (fibrinogen) are absent in the blood, the bleeding will not be stopped at the time jury resulting one can die too.
Blood should not be clotted inside blood vessels otherwise obstruction will come in blood circulation. The clot thickening inside the blood vessels of the injured part is called ghanastra and this condition is called ghanastrata. The ghanastra takes place in the heart is known as heart ghanastra and it affects the brain, it is known as brain ghanastra.