How red blood cells work

Posted on 2013-05-20 01:58:37

Techniques that enhance the number of red blood cells are one of the most common methods of doping in professional sports. Red cells are a major component of blood, and are primarily responsible for transportation of oxygen throughout the body. Red blood cells mainly have a protein called haemoglobin, which is manufactured from iron. The color of blood comes from this haemoglobin. The haemoglobin is able to absorb oxygen in the lungs, and then release this oxygen to the various parts of the body. Red blood cells also have proteins on their surface that determine the blood group of the individual. Depending on the type of protein (or specifically antigen) that is found on the red blood cells, blood group is said to be group A, B, AB or O (for blood group O, none of the other two antigens are present). Production of red blood cells Red blood cells are produced in the bone marrow, with the average development taking one week. The red blood cells are then released into the blood stream where they begin their oxygen-carrying function. A full cycle of a red blood cell takes approximately 20 seconds, say from lungs to the rest of the body and back to the lungs again. Red blood cells survive up to 120 days in the blood stream before they are replace by the newly produced cells from the bone marrow. The aging cells are removed from circulation by the spleen, liver and the bone marrow. The eventual by-products of the breakdown of red cells are iron, which is re-circulated for use, and bilirubin, which is transported to the liver. Red blood cell disorders Disorders of production – red blood cell disorders affecting the production include overproduction, underproduction or production of abnormal red blood cells.
  • Overproduction – polycythemia is a condition where excessive red cells are produced mainly due to a problem in the bone marrow. This makes the blood thicker, which slows down the movement of red blood cells hence transportation of oxygen.
  • Underproduction – red cell aplasia and aplastic anemia are conditions affecting the bone marrow where red blood cells are not produced. Red cell aplasia affects only the production of red blood cells while aplastic anaemia affects production of all cells by the bone marrow including white blood cells and platelets.
  • Abnormal red blood cells – there are various conditions whereby the red cells are abnormal which may affect the shape, oxygen-carrying capacity and reduce the lifespan.
Excessive destruction – the excessive destruction of red blood cells is generally referred to as haemolyisis. This may be caused by conditions that are in-born or due to acquired diseases such as malaria.