Anemia is a decrease in number of red blood cells (RBCs) or less than the normal quantity of hemoglobin in the blood.
Anemia is a condition that develops when your blood lacks enough healthy red blood cells or less than the normal quantity of hemoglobin in the blood.
Red blood cells are the main transporters of oxygen to organs and hence if red blood cells are deficient in hemoglobin your body doesn't get enough oxygen. The deficiency of oxygen can also be caused by decreased oxygen–binding ability of each hemoglobin molecule due to deformity or lack in numerical development. As hemoglobin found inside RBCs normally carries oxygen from the lungs to the tissues, anemia leads to hypoxia (lack of oxygen) in organs. Symptoms of anemia like fatigue occur because organs aren't getting enough oxygen. Since all human cells depend on oxygen for survival, varying degrees of anemia can have a wide range of clinical consequences.
There are several kinds of anemia, produced by a variety of underlying causes. The three main classes of anemia include excessive blood loss (acutely such as a hemorrhage or chronically through low–volume loss), excessive blood cell destruction (hemolysis) or deficient red blood cell production. All are very different in their causes and treatments. Iron–deficiency anemia, the most common type, is very treatable with diet changes and iron supplements.