Leukocytes vs Erythrocytes redirects here.
WBC (or White Blood Corpuscles) and RBC (Red Blood Corpuscles) are essential components of the blood with vital but distinct functions.
RBCs, also called erythrocytes, have a protein called hemoglobin. The blood gets its color when hemoglobin absorbs oxygen from the lungs. As the blood travels through the body, the hemoglobin releases the oxygen in the tissues. RBCs have a life cycle of 4 months and they appear in the form of flat indented discs.
The WBCs, also called leukocytes, handle more complex functions. They are the defense mechanism of the human body for fighting infections. There are different types of WBCs with varied life cycles and distinct functions. White blood cells also produce a special protein called antibody which recognize and fight the presence of foreign elements in the body.
edit Differences in Shape
RBCs are shaped like flat indented discs, while WBCs are generally irregularly in shape.
RBCs do not have a nucleus and there is no outer coat. In addition to a nucleus, the WBCs have a white buffer like coat, which is responsible for their nomenclature.
RBCs have no classification; they come in just one type. WBCs are present in various types, viz. neutrophils, basophils and eisinophils, which have distinct functions
The function of Red Blood Cells (RBC) in the body is to transport oxygen from the lungs to the tissues. Their life span is generally about 4 months and the body constantly replenishes RBCs as and when they are lost. RBCs produce a protein called hemoglobin, which absorbs oxygen from the lungs. Hemoglobin is also what gives blood its color.
The function of White Blood Cells (WBC) is to defend the body from various infections. They produce antibodies that help detect and fight the presence of foreign elements (say germs) in the body. They strengthen the defense mechanism, thereby improving the immune system of the body against germs. WBCs also help destroy cancer cells at the inception stages.
edit Blood Count
A complete blood count (also known as full blood count (FBC) or full blood exam (FBE) or blood panel) captures measurements for various components of blood, including RBC and WBC. Detailed information about "normal range" for WBC and RBC can be found here.
edit WBC Count (or leukocyte count)
WBC count is the number of white blood cells in the volume of blood. There are normally between 4×109 and 1.1×1010 white blood cells in a liter of blood, making up approximately 1% of blood in a healthy adult. This is also called leukocyte count and may be expressed as 4,000 to 11,000 cells per cubic millimeter (cmm).
edit RBC Count
RBC count is the number of red blood cells in a volume of blood. There are normally between 4.2×1012 and 6.9×1012 red blood cells in a liter of blood in an adult human male. This is also called erythrocyte count.
edit Significance of irregularity in count
An increase in the WBC count in blood signifies the presence of an infection, since the body produces more WBCs as it fights against the infection. A low WBC count may decrease the body's ability to fight disease-causing germs like bacteria and viruses.
Anemia is a decrease in normal number RBCs or less than the normal quantity of hemoglobin in the blood. In the various types of anemia, iron deficiency anemia is the most common. It occurs when the dietary intake or absorption of iron is insufficient, and hemoglobin (which contains iron) cannot be formed.