Biology Education

Difference between Red Blood Cells (RBC) and White Blood Cells (WBC)

Main Difference

Red blood cells(RBCs) and white blood cells(WBCs) are the main component of blood. But both are, in essence are totally different. For example, Red blood cells supply oxygen to the whole body, while white blood cells main function is to provide immunity. Red blood cell have no type but white blood cells can be divided into neutrophils, macrophages, monocytes, basophils, eosinophils, lymphocytes. Although both RBCs and WBCS are entirely different entities in every aspect but they are derived from same blood stem cell.

Red Blood Cells(RBCs)

redbloodcells3Also known as erythrocytes, is the most common and important component of blood for delivering oxygen to the whole body tissues. RBCs present in the blood travels throughout the body via circulatory system. Along with oxygen they also have a ability to bind with CO2 as well.  RBCs take O2 from our respiratory tract which then binds to the hemoglobin. Hemoglobin contains 4 subunits of an iron containing molecule called heme. Heme a subunit of hemoglobin have a capability of binding O2, one heme can bind one oxygen only. Therefore single hemoglobin can carry up to 4 O2 molecules. And the red color of RBCs is because of heme group.  Cell wall of RBCs are made up of lipids and proteins and they are biconcave in shape which allow them to move even from the narrowest vessels by providing stability, flexibility and deformability. In mammals, RBCs contain nuclei in their early stages as they mature they become anucleate and lose some of their organelles. RBCs are formed in bone marrow in adults while in embryo they are derived from yolk sac which later in embryonic life is formed by liver. They cannot multiply on their own so, the old cells can only be replace by the new cell formed in the bone marrow which leads them to shorter life span of 120 days.

White Blood Cells(WBCs)

whitebloodcellsWhite blood cells or leukocytes are involved in providing immunity. WBCs protect us from infectious and foreign organisms. WBCs are present in blood and lymphatic fluid. They do not contain heme, so they are colorless. The WBCs count in blood varies with type of disease. WBCs only comprises 1% of total blood as compared to RBCs which is 40-50% still this 1% is important for maintaining normal body immune system. If WBCs level becomes below 1% then our body is vulnerable to different infection as in case of HIV where WBCs counts drops to critical level. WBCs are of two different types granulocytes and agranulocytes. Granulocytes further divides into following types: neutrophils, basophils, eosinophils, mast cells. Agranulocytes are of two types named monocytes and lymphocytes. All the WBCs contain nucleus, they have shape according to their function. They are produced  in bone marrow but they have ability to multiply to destroy foreign invader. Their life span varies between hours and days except lymphocytes which can survive up to weeks or years.

Key Differences

  • RBCs main function is to deliver oxygen to the tissues of body while WBCs provide immunity and to maintain the body’s natural immune system.
  • In blood, there are more than 5 million RBCs, while WBCs are only 4000-11000 in the same quantity of blood.
  • RBCs are biconcave in shape and are anucleate while WBCs are irregular in shape and contains nucleus.
  • Red color of RBCs are because of heme. WBCs do not have heme.
  • RBCs are flexible and easily deformable which help them to pass through the smallest vessels while WBCs can not change its shape.
  • Decrease in RBCs count leads to anemia while decrease in WBCs count leads to increased risk of infections.

Video Explanation

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