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| Red Blood Cells (RBC's) |
The red blood cells are produced in the bone
marrow. The main function of the red blood cell is to transport oxygen to the
tissues. Production of red blood cells is called erythropoiesis.
Erythropoiesis is initiated by a hormone produced by the kidney called erythropoietin.
When a person's hemoglobin level is below normal, his tissues will not receive
an adequate supply of oxygen, and this will stimulate the kidneys to increase
their production of erythropoietin. The increased erythropoietin will then
stimulate the stem cells of the bone marrow to differentiate into the
pronormoblast, and there will be an increased number of red blood cells
produced. As the red cells are maturing they undergo several cellular division.
Once the orthochromic normoblast stage is reached, however, the cell is no
longer capable of mitosis but will continue to mature in the bone marrow. The
reticulocyte remains in the marrow for approximately two days and is then
released into the peripheral blood. The red cells of the circulating blood have
a lifespan of approximately 120 days, +20 or -20 days.
Size:
6.7 to 7.7 micro in diameter.
Cytoplasm: Pink in color.
Cytoplasm: Pink in color.
The mature red blood cell is a
non nucleated, round, biconcave cell.
