White Blood Cells.ppt White Blood Cells Blood Cells

White Blood Cells

1. Dr zuha sarfaraz metlo

2. Objectives
➢To understand about leukocytes.
➢To know about their origin and structure.
➢To understand about their function.

3. White Blood Cells (Leukocytes)
➢Also called the white blood cells, Leukocytes are
important blood components and also play a key
role in the immune system.
➢There are several different types of leukocytes,
each having a specific function in body.

4. leukocytes

5. ➢If body has a high count of leukocytes in blood, it
could be an indication of the presence of an
underlying disease or infection.
➢ When body have a low count (leucopenia), it
could be an indicator of some medical problems.

6. Leukocytes
➢Normal human blood contains:
4000 - 10,000 leukocytes/ml
7000white blood cells per microliter of blood
5million red blood cells per microliter of blood
➢Like all blood cells, they are produced in the bone
marrow.
➢Leukocytes are divided into five classes based on
morphological and special characteristics when
stained.

7. ➢The five classes of leukocytes are:
➢Neutrophils (62percent
➢Eosinophils (2.3%)
➢Basophils ( o.4%)
➢Monocytes 9%)
➢Lymphocytes (20%-45%)
Plasma cells for immunity

9. ➢Collectively, neutrophils, eosinophils, and
basophils are known as granulocytes due to the
presence of granules in their cytoplasm.
➢ In addition, monocytes and lymphocytes are also
known as mononuclear cells or agranulocytes due
to absence of granules.

10. Types of Leukocytes
➢Neutrophils
➢Within 12 hours of being discharged from the
marrow into the bloodstream, neutrophils
migrate into the extravascular tissue.
➢Tissue neutrophils are activated
by chemoattractants at the site of injury.
➢Neutrophils ingest bacteria by phagocytosis and
then release enzymes (such as lysozyme) to
destroy the bacteria.

11. Neutrophil

12. ➢Eosinophils
➢Eosinophils migrate from the marrow through the
blood into the extravascular tissue, and they
survive there for weeks.
➢ Again, chemoattractants direct the movement of
eosinophils, They do not ingest organisms, but
they do exert cytotoxic effects on them.

13. Eosinophil

14. ➢Basophils
➢Basophils are morphologically similar to mast
cells, and along with other granulocytes,
basophils are motile cells with phagocytic
properties.
➢They may migrate into extravascular tissues
where they may be stimulated by complexes of
antigens that are bound to IgE.

15. Basophil

16. ➢Monocytes
➢Monocytes are larger than other leukocytes, and
they mature into macrophages once they are
released into the bloodstream.
➢Monocytes then migrate to tissues, particularly
the liver, lymph nodes, and lungs, where they may
stay for days or years.

17. Monocyte

18. ❖Here, the monocytes are actively phagocytic, and
they ingest particulate matter.
❖Monocytes are also important to the immune
response. They ingest and process antigens and
are involved in antigen presentation, by B- and T-
lymphocytes.

19. ➢Lymphocytes
➢Two main types of lymphocytes are
➢ B-cells
➢T-cells.

20. Lymphocytes

21. ❖B-cells are characterized by the presence of
immunoglobulins on their surface, and upon
stimulation with antigen, they are transformed
into plasma cells.
❖Plasma cells are then able to secrete antibodies
specific to the antigen.

22. ❖T-cells take part in cell mediated immune
response, which does not depend on the
presence of circulating antibodies.

23. Immunity
➢The ability of an organism to resist disease,
either:
➢Through the activities of specialized blood cells or
antibodies produced by them in response to
natural exposure or inoculation (active
immunity)
➢By the injection of antiserum or the transfer of
antibodies from a mother to her baby via the
placenta or breast milk (passive immunity)

24. Disorders of Leukocytes
➢A number of disorders can impact these
important cells and typically occur when:
➢White blood cell count is low
➢White blood cell count is high
➢White blood cells are not functioning properly

25. Leukopenia
➢A low white blood cell count, or leukopenia, is a
decrease in disease-fighting cells (leukocytes)
circulating in your blood.

26. Causes
➢A low white blood cell count usually is caused by
one of the following:
➢Viral infections that temporarily disrupt bone
marrow function
➢Congenital disorders characterized by diminished
bone marrow function
➢Cancer or other diseases that damage bone
marrow

27. ❖Autoimmune disorders that destroy white blood
cells or bone marrow cells
❖Overwhelming infections that use up white blood
cells faster than they can be produced
❖Drugs that destroy white blood cells or damage
bone marrow

28. ➢Because a chronic very low white blood cell count
makes body vulnerable to infections.
➢Always wash your hands regularly and
thoroughly.
➢Wear a face mask and avoid anyone with a cold or
other illness.

29. Leukocytosis
➢High white blood cell count is an increase in
disease-fighting cells (leukocytes) circulating in
blood. High white blood cell count is also called
leukocytosis.

30. Leukocytosis
➢A high white blood cell count usually indicates:
➢An increased production of white blood cells to
fight an infection
➢A reaction to a drug that increases white blood
cell production
➢A disease of bone marrow, causing abnormally
high production of white blood cells
➢An immune system disorder that increases white
blood cell production

31. Leukemia
➢Leukemia is cancer of the body's blood-forming
tissues, including the bone marrow and the
lymphatic system.
➢Many types of leukemia exist. Some forms of
leukemia are more common in children. Other
forms of leukemia occur mostly in adults.

32. ➢Leukemia usually starts in the white blood cells.
➢White blood cells are potent infection fighters —
they normally grow and divide in an orderly way,
as body needs them.
➢People with leukemia, the bone marrow produces
abnormal white blood cells, which don't function
properly.

33. Symptoms
➢Fever or chills
➢Persistent fatigue, weakness
➢Frequent infections
➢Losing weight without trying
➢Swollen lymph nodes, enlarged liver or spleen
➢Easy bleeding or bruising
➢Tiny red spots in your skin (petechiae)
➢Excessive sweating, especially at night
➢Bone pain or tenderness

34. Petechiae and Bruise

35. Causes
➢Scientists don't understand the exact causes of
leukemia.
➢ It seems to develop from a combination of
genetic and environmental factors.

36. ●In general, leukemia is thought to occur when
some blood cells acquire mutations in their DNA.
●The abnormalities cause the cell to grow and
divide more rapidly and to continue living when
normal cells would die.
●Over time, these abnormal cells can crowd out
healthy blood cells in the bone marrow, leading to
fewer healthy blood cells and causing the signs
and symptoms of leukemia.

37. Predisposing Factors
➢Genetic disorders. 
➢Certain blood disorders.
➢Exposure to high levels of radiation. 
➢Exposure to certain chemicals. 
➢Smoking.
 
➢Family history of leukemia

38. Thank you

39. References
●Text Book of Medical Physiology, Guyton & Hall.