This video clip explains what anemia is. The video starts off with revealing erythropoietin, a hormone that controls the production of red blood cells. This process is known as erythropoiesis. Erythropoietin is produced in the kidneys and promotes red blood cell formation in the bone marrow. As shown in the video, when the level of healthy red blood cells (RBCs) in the body becomes too low, anemia occurs. Anemia is one of the most common blood disorders that can cause a variety of complications, including fatigue and stress on bodily organs.