classification %, characteristic, functions, variation, leukaemia

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.