White blood cells (WBCs)

White blood cells (WBCs)

Blood Circulation :
(iv.) Blood cells
(i.) Arterial system


60-70 %


0-1 %


3-4 %


25-30 %


5-10 %

          In our body, WBCs is helpful to fight against the diseases. It is known as the second protector (guard). First protector is mucus membrane present in the skin. Its life is not certain. Sometimes, it lives for only few hours or sometimes lives for few months. These cells keep on growing and destroying. They remain active continuously due to which their shape goes on changing and they absorb bacteria and other carbonic substances and then destroy them. They are found about 5000 to 8000 in number per cubic ml blood of a healthy person. They are the biggest among all the three blood cells, but less in number. There are many types of it given below -  

Functions of WBCs-

  • Basophils protects from wounds or swelling. They are found in little number in leucocytes. They secrete many types of important fluids. Among them, one is heparin that prevents blood blotting.
  • Neutrophils are helpful in fighting against diseases like a soldier.
  • Eosinophils are helpful or able to protect our body from bacteria and to prevent allergy.
  • Lymphocytes generate anti body that stop bacteria to enter inside the body and destroyed them too.
  • Monocytes also give strength to our body to protect from diseases.

White blood cells-WBCs:

        White blood cells or leucocytes are larger than the red blood cells. Their diameter is about 10 µ m micrometer but their number is less comparison to red blood cells. They are 4000 to 11000 per cubic mm3 in the blood of an adult person. The numbers of white blood cells reach to the 25000 per cubic millimeter by increasing. This augmentation of white blood cells is called leucocytosis.  

     White blood cells are colorless and transparent and there are more nucleuses than one nucleus in them. Their shape is changeable and they are live and reach in the tissues by passing through the walls of ducts. These cells originate in the bone morrow or lymph gland. 

     Protecting body by swallowing or destroying pathogenic organism and poisonous substances came into the blood is the main function of white blood cells. There is an augmentation in the number of white blood cells during the work of phagocytosis.

White blood cells or leucocytes have been divided into two groups. 

1. White blood cells or granulocytes or polymorphonuclear leucocytes

2. Agranulocytes or mononuclear leucocytes

White blood cells or granulocytes or polymorphonuclear leucocytes:

        Granules are found in their cytoplasm so they are called granulocytes. There are two or more than two lobes in their nucleus so they are called polymorphonuclear leucocytes. These cells make about 75 percent portion of the total number of white blood cells. They originate from the special cells-myeloblast of bone marrow and they live alive till 21 days.

Granular white blood cells are of three kinds on the base of stain capacity.

1. Neutrophills

2. Eosinophils

3. Basophils

Neutrophils: (60-70%)

        These are the cells which are stained easily by the passive stainer. Nucleus is stained of purple color and there are two to five lobes in it which are connecting to each other by thread like formations. Cytoplasm is light colored stain in which pink to blue-black colored very small particles are found in it. They have the capacity to swallow small viruses and other poisonous substances. This capacity is called phagocytosis. So they are called phagocytes too. There is amobide movement it and they can go out from the blood circulation for gathering on the place of infection by emerging from the cellular walls.

Eosinophils, (1-6%):

        These are the white blood cells which are stained by the iosin (acid). Their particles are rough and coarse which appear red in color. There are nucleuses of two lobes in them which are connected to each other by a thick thread. The nucleus is blue stained. There is an augmentation in the number of iosenofills in the allergic condition as bronchial asthma and infection of worms. 

Basophils: (0-1%)

        Basiohils get purple bluish in color by absorbing alkali pigment. Their particles are thick. There is a nucleus of two or three lobes in the shape of kidney in them. There are heparin, histamine and substance which do slow reaction (SRS-A) in their granules. SRS-A produce some allergic symptoms as contraction in the breathing pipe. Basophlis takes part in too much sensitiveness reaction and play an important role in providing immunity for the paracytes.

Agranulocytes or mononuclear leucocytes:

        There is no granule or bead in the cytoplasm of these cells. They are of two kinds.



Lymphocytes: (20-30%)

        There is one big or circular nucleus in them which cover most of portion of the cell. There is less cytoplasm and it is on the edge. They are of two kinds- small and big. Their nucleus is dark blue stained whereas cytoplasm is yellow. They originate from the cells named heamocytoblast of bone morrow and from this place they reach into the lymphoid tissues by the blood circulation and become active there and protect from the external substances (antigen). Most of lymphocytes are found in the lymph nodes, spleen, thymus gland, tonsilis, adenoids and lymphoid tissues of gastrointestinal tract (GIT). There is some amoeboid movement in it but these are not phagocytic. They are associated with the building of antibodies.    

Monocytes: (3-5%)

        These are the biggest mononeuclear cells in the white blood cells. their nucleus is comparatively small in kidney shaped and mostly is situated on the one side of cells. Mostly, they are stained with thickness and appear cancellate in which there are vacuoles. There are both kinds of movements-amoeboid and phagocytic in them and they make the main part of reticuloendothelial system. They originate from the monoblast cells of bone marrow.   

Functions of white blood cells:

        White blood cells of neutrophlis and monocytes class protect body from the attack of bacteria. There is phagocytosis in them by which these devour bacteria and external substances. This is the reason that they are called phagocytes. They expel out broken tissues in by the same process.

      Lymphocytes produce antibodies by which they protect body. There is no devouring power in them. 

Platelets or thrombocytes:

       These are the small cells one fourth of red blood cells (erethrocytes) in size. Their number in the blood is 250000 per cubic milimtere (mm3). There is no nucleus in the platelets. Their average life period in the blood circulation is from 5 to 9 days.  

     The platelets or thrombocytes originate from the cells named hemocytoblast of bone morrow like the lymphocytes. Helping in the process of haemostasis (making the clot of blood) is the main function of these cells.