The blood circulates all over the body. The main function of the blood is to provide food, oxygen, hormones and other chemicals to all the body's cells. Bone Marrow is known as the “blood cell factory” of the body. Its main function is to fill the cavities of bones. It is true that blood cells are originated and produced from a single "stem cell". They have the tendency to grow and take form of different type of blood cells. They are white blood cells and red blood cells.

The basic aspect of stem cell is that it can grow and has the tendency to  renew itself as per the individual requirement of every body structure. Red blood cells are called erythrocytes and holds the basic function of carrying oxygen from the lungs to all the parts of the body. If the body lacks the number of red blood cells that are required for the basic functioning of the body, then the condition may lead t

If you don't have enough red blood cells, then it can cause a very serious disorder called anemia. If you will suffer from this condition then you will normally tend to look very pale and the condition may make you feel tired, dizzy, irritable and short of breath. RBCs that is the short form of Red Blood Cells also hold the function of picking up wastes on their way around the body, and then these waste products are carried by them  to  lungs so that they can be exhaled out in the form of  carbon dioxide.

White blood cells that are also known as leucocytes or WBC, are famous for playing the role of body's infection fighters. There are mainly three types of white blood cells: granulocytes, lymphocytes and monocytes.
The main function of white blood cell is to make our body immune and get rid of all the disease-causing bacterias, viruses, fungi. They are also responsible for destroying the body's dead or defective cells.

Platelets, are those small cells that play a major role in the prevention of bleeding by making a layer on the injury, that is known as blood clot. The process is done immediately after an injury is caused. When an injury is occurred, and the blood vessels get damaged then platelets immediately run to that particular area and form a layer to stop further  bleeding.