Blood Cell Disorders: Anemia

Diagram of normal and anemic amount red blood cells

Anemia is a condition in which the oxygen-carrying capacity of blood is reduced.  All of the many types of anemia are characterized by reduced numbers of RBCs. The person feels fatigued and is intolerant of cold, both of which are related to lack of oxygen needed for ATP and heat production. Besides that, the skin of the person with anemia will appears pale due to the low content of red colored hemoglobin circulating in skin blood vessels. There are many types of anemia such as iron-deficiency anemia, megaloblastic anemia, pernicious anemia, hemorrhagic anemia, hemolytic anemia, thalassemia and aplastic anemia. In some cases of sickle cell anemia, thalassemia, and aplastic anemia, bone marrow transplantation may be used. In this procedure, bone marrow cells taken from a donor are injected into the child's vein. They then travel through the bloodstream to the bone marrow and begin producing new blood cells. Among the most important causes and types of  anemia are the following: 

• Inadequate absorption of iron, excessive loss of iron, increased iron requirement, or insufficient intake of iron causes iron-deficiency anemia, the most common type of anemia. Women are at greater risk for iron-deficiency anemia due to menstrual blood losses and increased iron demands of the growing fetus during pregnancy. Gastrointestinal losses, such as those that occur with malignancy or ulceration, also contribute to this type of anemia. 

• Inadequate intake of vitamin B or folic aced causes megaloblastic anemia  in which red bone marrow produces large, abnormal red blood cells. It may also be caused by drugs that alter gastric secretion or are used to treat cancer. 

• Insufficient hemopoiesis resulting from an inability of the stomach to produce intrinsic factor, which is needed from absorption of vitamin B in the small intestine,  causes pernicious anemia.

• Excessive loss of RBCs through bleeding resulting from large wounds, stomach ulcers, or especially heavy menstruation leads to hemorrhagic anemia. 

• RBC plasma membranes rupture prematurely in hemolytic anemia. The released hemoglobin pours into the plasma and may damage filtering units int he kidney. The condition may result from inherited defects such as abnormal red blood cell enzymes, or from outside agents such as parasites, toxins, or antibodies from incompatible transfused blood.

• Deficient synthesis of hemoglobin occurs in thalassemia.,a group of hereditary hemolytic anemia. The RBCs are small, pale, and short-lived. Thalassemia occurs in population from countries bordering the Mediterranean Sea.

• Destruction of red bone marrow results in aplastic anemia. It is caused by toxins, gamma radiation, and certain medications that inhibit enzymes needed for hemopoiesis. 

Symptoms of anemia 

Source: http://www.youtube.com/watch?v=_ZV5140OykE