Tutorial Answer 5

Anemia refers to the lack of sufficient oxygen delivery by the hemoglobin-red blood cell system. Sickle cell disease is just one form of anemia. Other forms of anemia result from failure of the body to synthesize enough hemoglobin, parasitic invasions of red blood cells, lack of iron in the diet (since iron in the ferrous state is the main component of the porphyrin ring, and is the binding site for oxygen). Other physiological or anatomical conditions can restrict oxygen delivery, including occluded arteries due to cholesterol build-up, emphysema (deterioration of the lung tissue, particularly a result of smoking or long-term exposure to air pollutants, preventing adequate diffusion of oxygen across the lung membranes). These conditions are not anemias, though the effect of reduced oxygen delivery to the tissues is the same.