There are two types of blood cells present in a human body. They are the red blood cells and the white blood cells. The red blood cells are the most common cells present in the body and are circular and fairly uniform in size. The white blood cells are also circular in shape but they are colorless and different in functioning than the red cells.
Structure of Red Blood Cells: –
The diameter of a typical human erythrocyte disk is 6–8 µm, much smaller than most other human cells, a typical erythrocyte contains about 270 million hemoglobin molecules, with each carrying four heme groups. Adult humans have roughly 2–3 × 1013 red blood cells at any given time. Women have about 4 million to 5 million erythrocytes per cubic millimeter or micro liter of blood and men about 5 million to 6 million; The red blood cells store collectively about 3.5 grams of iron, more than five times the iron stored by all the other tissues combined. The process by which red blood cells are produced is called erythropoiesis. Erythrocytes are continuously being produced in the red bone marrow of large bones.
The mature red blood cell consists primarily of 90% hemoglobin. The membrane is composed of lipids and proteins. In addition, there are numerous enzymes present which are necessary for oxygen transport and cell viability. The main function of the red cell is to carry oxygen to the tissues and return carbon dioxide from the tissues to the lungs. The protein hemoglobin is responsible for most of this exchange. Normal red blood cells are round, have a small area of central pallor, and show only a slight variation in size. As the relative amount of hemoglobin in the red cell decreases or increases, the area of central pallor will decrease or increase accordingly.
Structure of White blood cells: –
The white blood cells are also called as Leukocytes and they defend the body against bacteria and other viruses. Compared to the red blood cells, the white cells are produced in less number. One white blood cell is formed in comparison to the 700 red blood cells formed. They are large as compared to the red blood cells. The WBC’s measure about 8 µm and are produced in the bone marrow. They are circular in shape and are also rigid in structure. The walls of the WBC’s are thicker than those of RBC’s. The white blood cells store very little amount of iron as compared to RBC’s.
This description clarifies the structure of blood cell morphology in brief. Apart, from these, there are several other minute features of the blood cell morphology.