This document classifies and describes the types of white blood cells (WBCs), also known as leukocytes. It discusses the normal counts of each type of WBC, their structures, functions, and variations seen in conditions like infection, malnutrition, and leukemia. The main types of WBCs are granulocytes (neutrophils, eosinophils, basophils) and agranulocytes (lymphocytes, monocytes). Neutrophils are the most abundant WBC and function in phagocytosis and inflammation. Leukemia is a cancer of the blood characterized by an abnormal increase in immature WBCs in the bloodstream.

1. by – Dr .F. B. Irani

2. Objectives
 Classify leucocytes, with its % in blood
 describe the structure and functions of
leucocytes
 normal count
 variations

3. WBCs
Granulocyte Agranulocyte
1. Neutrophils 1. Lymphocytes
2. Eosinophils 2. Monocytes
3. Basophils

4. Normal count of WBCs :-
- At birth- 10,000- 25,000/mm3
-Adults – 4,000 – 11,000/mm3

5. WBCs DLC(%) Absolute
count
(per mm3)
Neutrophils 50 - 70 2,000 – 7,500
Eosinophils 1 – 4 40 – 440
Basophils 0 – 1 20-80
Lymphocytes 20– 40 1,500 – 4,000
Monocytes 2 - 8 500 - 800

6. Neutrophils- commonly called polymorph.
Diameter – 10 - 14 μm
Nucleus – multilobed ( 2-6), Lobes are connected
by chromatin filaments.
Cytoplasm – pale bluish with
violet-pink fine granules .
Enzymes are filled in granules.

7. Function – 1) Phagocytosis
 Engulf foreign particles, bacteria and digest them.
 Constitutes first line of defence.
2) Reaction of inflammation
 release leucotrienes, prostaglandins, thromboxanes.
 Which causes vasodilatation, oedema.
3) Febrile reaction –
 produces fever-producing substance called endogenous
pyrogen in response to bacteria.

8.  4. Sex determination – in females, drumstick
appendage of chromatin is attached to nuclear lobe.
 5. Role of nourishment of tissue cells -neutrophilis
along with plasma proteins produces trephones or
carrel which are essential for tissue cells.

9. Eosinophils – also called acidophilis.
Diameter – 10 - 14 μm
Nucleus –bilobed , connected by chromatin filaments
looks like spectacle.
Cytoplasm – appears bright pink
with coarse, deep red granules .
They contain histamine,
Lysosomal enzymes, ECF-A.

10. Functions – 1) Mild Phagocytosis – as they are less motile.
2) Role in parasitic infestations – produces lethal substances
 Major basic protein(MBP) – larvicidal
 Eosinophil cationic protein (ECP)- destroys
helminthes & is neurotoxin.
 Eosinophil peroxidase – destroys adult helminthes,
bacteria and tumour cells.
 Eosinophil derived neurotoxin- destroys nerve
fibers.

11. 3) Role in allergic reaction
 detoxify mediator of allergy
 destroys antigen-antibody complexes
 prevent spread of local inflammation.
4) Role in immunity –
 provide mucosal immunity in GIT,RT, UT

12. Basophils -
Diameter – 10 - 14 μm
Nucleus – irregular, may be bilobed or trilobed, boundary
not clearly defined & covered by coarse granules.
Cytoplasm – bluish , filled with plenty
coarse, deep blue coloured granules .
containing heparin, histamine and
chondroitin sulphate

13. Functions - 1) Mild phagocytic function.
2) Role in allergic reaction-release histamine, bradykinin,
SRS-A, 5HT, that causes allergic reaction
3) Role in preventing spread of allergic inflammation
 releases chemotactic factor that causes eosinophils to
migrate towards the inflamed allergic tissue. Which
then prevent.
4) Release of heparin – which prevents clotting of blood.

14. Lymphocytes – two types -large & small.
Diameter – 10 - 14 μm of large & 7-10 μm of small
lymphocytes.
Nucleus –large round ,single completely filling the cell.
blue coloured like ink-spot appearance.
Cytoplasm –scanty less than nucleus ,
light blue as crescent around nucleus ,
no granules .

15. Functions – Imp. role in immunity. Functionally are
classified into two types:
B lymphocytes and T lymphocytes.
Functions of B lymphoctes – responsible for humoral
immunity by producing antibodies(gamma globulins)
Functions of T lymphoctes – responsible for cellular
immunity against virus, bacterial infections, tumour cell.

16. Monocytes -
Diameter –largest, leucocytes in peripheral blood
12 - 20 μm
Nucleus – large, single , eccentric in position kidney
shaped. With chromatin network.
Cytoplasm –abundant, pale
blue clear no granules, may
contain fine purple dust like
granules.(azur granules)

17. Functions – 1) Phagocytosis
2) Role in tumour immunity – they kill tumour cell after
sensitization by lymphoctes.
3) Synthesis of biological substances – they
synthesize cytokines, complement factors, growth
factors, interleukins and enzymes for wound
healing.
4) Antigen presenting cell – this first step in activation
of cellular immunity.

18. Variation in WBCs
Leucocytosis - total WBC count > 11,000/mm3
Physiological causes -
1) Age - at birth WBC count is about 18,000/mm3
which decreases to adult level at 5-10 years .

19. 2) Exercise - count is increased due to disruption of
margination.
3) After food intake, Mental stress, anxiety, Exposure to
low temperature - causes increase in count .
4) Pregnancy - at full term pregnancy, menstruation,
lactation.

20. Pathological causes
1. Acute bacterial infections - by pyogenic organisms,
2. Acute haemorage ,
3. Burns,
4. Postoperative period ,
5. Tuberculosis ,
6. Glandular fever .

21. Leucopenia - total WBC count < 4000 /mm3 .
Causes of leucopenia -
1. Infection by non – pyogenic bacteria especially typhoid
fever and Paratyphoid fever .
2. Viral infections such as influenza , smallpox , mumps,
3. Protozoal infections .
4. Starvation and malnutrition .
5. Aplasia of bone marrow.

22. 6. Bone marrow depression due to :
- drugs - chloromycetin & cytotoxic drugs
- Exposure to X – rays
- Chemical poison - arsenic ,dinitrophenol & antimony.
Leukaemia - is a malignant disease of blood with
increase in WBCs. Immature WBCs are present in
the peripheral blood .Total WBC count is usually
above 1,00,000 to 3,00,000 /mm3 .

23. SAQ:- 1. Functions of WBC,
2 Functions of Neutrophilis,
3. Leukaemia, 4. Leukaemoid reaction,
LAQ:- 1. Describe various functions of WBCs.
2. Describe different types of WBCs.