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RED BLOOD CELLS |
Perhaps one of the most important part of the body is red blood cells. Obviously, we wouldn't be able to survive without it. That is because red blood cells are the main organelle that supplies all the body's tissues and cells with oxygen, which is required in many important operations, including metabolism and even aids in getting rid of bacteria and harmful wastes. Obviously, red blood cells occupy a significant portion of the human blood. The cells are round, with a dent in the middle, almost, but not quite, like a hole (see picture on the right). The shape of the RBC is an important part of the cell's function. Even more interesting is the fact that RBC's are the only cells that have no nucleus. That is because they don't reproduce. So why is it that we don't run out of blood, even if we get injured? The answer is simple. A red blood cell is made up of red pigments, known as as hemoglobins. Each hemoglobin is made up of 4 iron, known as hemes, and proteins, known as globins. |
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The 4 hemes are each attach to 1 globin, forming what is known as a polypeptide chain, a chain of amino acids held together by peptide bonds. This structure helps the red blood cell to carry more oxygen than it otherwise could. This complementary to the cell's structure. There are two important points about the structure of the RBC. For one, as previously stated, it has no nucleus. This gives the cell more space to hold more oxygen. Also, the lack of nucleus reduces the weight of the cell greatly, allowing the cell to be much faster in motion. RBC's die after an average of 120 days. After that, they are transported to the liver, where they are broken down and used to build new cells. Millions of cells are created every second through the bone marrow. |
| This happens primarily in the flat bones in the body such as the skull, the sternum, and the pelvis. Red blood cells lose their organelles, including mitochondria and the nucleus, during maturation, which takes about 1-2 days in the bone marrow, to become specialized. Old erythrocytes are also removed from circulation mainly by bone marrow and the spleen through phagocytic cells. | |
Secondly, the red blood cell does not have mitochondria and other organelles that may otherwise be present in a normal cell. Mitochondria's main purpose is to create energy through the respiration, which requires oxygen. Since the RBC doesn't do much other than transport oxygen, it wouldn't be suitable for it to have a mitochondria, espesically since the RBC would waste much more oxygen. Therefore, RBC depend on anaerobic respiration, instead of aerobic respiration. In anaerobic respiration, oxygen is not needed and would be much suitable for red blood cells. |
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Red blood cells, also known as erythrocytes, is flexible, which allows it to travel to hard organelles and through small capillares. Erythrocytes, RBCs, are around 7.5 microns in diameter and have an odd shape. This odd shape allows facilitated oxygen transfer and for better flexibility in small capillaries. There are normally around 3.9-5.5 million RBCs per microliter in women and 4.1-6 million per microliter in men, each lasting about 3 to 4 months (120 days) |
Abnormalities Even though millions of red blood cells are produced every second, and each lasts about 120 days, the body may lack in red blood cell numbers. Such a condition is known as anemia. Anemia is caused by the reduction of RBCs in the blood. The main reason for this condition is caused by lack of nutritutions, especially iron and several vitamins, including B12. These cause reduction in hemoglobin formation. When these nutrients are not existant in a diet, the bone marrow lacks the elements required to produce RBCs and often can't keep up with the body's demand. Some symptoms of anemia include fatigue, chest pain, and shortness of breath. There are several treatments for anemia, most notiably is perhaps a blood transfusion. |
