Download Types of White Blood Cells WBCs.

Leukocytes (White Blood Cells)
Types of leukocytes
Production (Leukopoiesis )
Functional characteristics of the
different leukocytes
Types of White Blood Cells WBCs.
Five types of white blood cells are normally present in the blood
 On average, there are 4000-10000 WBC/l of blood.
Average no.=7000 l of blood
 Remember they account for about 1% of total blood
cells.
Leukocytosis
Leukopenia
***megakaryocyte similar to WBCs, will give platlets
 Compare them to RBCs.
 Storage pool
Types of White Blood Cells WBCs.
***Conspicuous nucleus
**granulocytes and monocytes protect body by ingestion (phogocytosis) of invading
organisms( for example bacteria). They are formed in bone marrow.
** lymphocytes protects body through immune system. They are formed in lymphogenous
tissues (lymph glands, spleen, tonsils, thymus, Peyer’s patches in intestinal wall.
Genesis of the White Blood Cells Leukopoiesis
Genesis of white blood cells. The different cells of the
myelocyte series
are 1, myeloblast; 2, promyelocyte; 3,megakaryocyte;
4, neutrophil myelocyte; 5, young neutrophil
metamyelocyte; 6, “band” neutrophil
metamyelocyte; 7, polymorphonuclear
neutrophil; 8, eosinophil myelocyte; 9,eosinophil
metamyelocyte; 10,polymorphonuclear
eosinophil; 11,basophil
myelocyte; 12,polymorphonuclear basophil; 1316,stages of monocyte formation.
Life Span of the White Blood Cells
 Granulocytes stay in blood for 4-8 hours and in the tissues 5 days.
When there is serious infection their whole life span is shortened to
few hours
 Monocytes stay in the blood for 10-20 hours and then they leave to
different tissues where they form tissue macrophages. Tissue
macrophages can live for months. If there is infection these
macrophages may die earlier.
 Lymphocytes circulate between blood and lymphoid tissues
through lymph and they survive for weeks and months
Leukocytes functions
•Neutrophils: first responders/ bacteria
•Eosinophils: parasites
•Basophils: allergies
•Lymphocytes: viruses, cancer (bad
cells) antigens foreign antigens
•Monocytes: phagocytes during
inflammation
Appearance:
Contain fine granules
Multilobulated nucleus 3-5 lobes
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Role of neutrophils
Mature cells
The first responder
mainly attack bacteria and destroy them by phagocytosis
Neutrophilia; after the onset of acute, sever inflammation, neutrophils number increases in the
blood 4-5 folds above normal
62% of WBCs in blood
4000-5000 cells/ul
Neutrophils recruitment to the area of inflammation
1. Tissue injury occurs, whether caused by
bacteria, trauma, chemicals, heat, or any other
phenomenon.
2. Injured tissues release chemical substances
e.g.
• some of the bacterial or viral toxins
• degenerative products of the inflamed tissues
themselves
• several reaction products of the “complement
complex” activated in inflamed tissues
• several reaction products caused by plasma
clotting in the inflamed area, as well as other
substances.
3. These chemical substances will induce the
release of neutrophils from bone marrow into
blood stream.
4. These chemical substances especially histamine
from tissue mast cells will increase the
permeability of tissue capillaries allowing
neutrophils to migrate to the damaged tissues.
5. The same chemical substances
release from the damaged area
will attract neutrophils. (this
process is called Chemotaxis.
6.
Neutrophils will destroy the
bacteria:
a) Phagocytosis
b) Releasing bactericidal agents
that kill most bacteria ( most of
them are oxidizing agents).
e.g. of these bactericidals are
superoxide (O2−), hydrogen
peroxide (H2O2), and hydroxyl
ions (OH− and hypochlorite (ClO-)
• myeloperoxidase
Diapedesis
1. Chemical substances ( chemokines) e.g. TNf and IL-1 from inflamed tissues are released.
2. these chemokines will induce expression adhesion molecules selectins and intracellular adhesion molecule- 1
(ICAM-1) on endothelia cells of capillaries.
3. These adhesion molecules attach to their
complemntray integrin molecules on neutrophils
4. chemokines also increase the permeability of capillaries
( histamine) allowing neutrophils to pass into
interstitial flowed by diapedesis
5. Filially, the concentration gradient of chemokines cause
Movement of neutrophils to the injured area by a process
Called chemotaxis
Movement of WBCs by Chemotaxis towards an area of tissue damage
• Chemical substances (chemotactic substance,
chemotaxins) found and produced in the tissues
or released by other leukocytes that attract
WBCs toward these chemicals.
• Chemotaxins include
1. Bacterial or viral toxins
• Degenerative products of inflamed tissues
• Reaction products of ‘complement complex’
• Reaction products of plasma clotting
Chemotactic signals effective till 100m
Amoeboid motion of Leukocytes
neutrophils can phagocytize 3-20 bacteria and macrophages
can phagocytize up to 100 bacteria
http://harunyahya.com/en/Books/3752/the-miracle-in-the-cell/chapter/4966
Factors determining if phagocytosis will take place or not
• 1. Selective – Natural structures is
protected from phagocytosis by smooth
surface and protective proteins. While
foreign bodies have rough surfaces and
no protective proteins so they are liable
to be phagocytized.
• 2. Antibodies adhere to surface of
bacteria and make them susceptible for
phagocytosis (opsonization).
Eosinophils
2.3% of WBCs
Very large rosy granules
Bilobed nucleus
Responsible for protection against parasitic infection
Their granules contain:
1.Hydrolytic enzymes, which are modified lysosomes
2. highly reactive forms of oxygen that are especially
lethal to parasites; and
3. highly larvacidal polypeptide called major basic protein.
Eosinophils are attracted by chemotactic factor released by
basophils and mast cells toward allergic tissues.
They detoxify the substances that released during allergic
reaction. Also they engulf antibodies-antigens complexes so
they help in reducing spread of allergic reaction
Basophils
• Large histamine-containing granules
• Affinity for basic dyes so they stain purplish
black (baso = basic).
• Similar in function to mast cells. Mast cells are
found in the tissues.
• Both mast cells and basophils liberate histamin
and heparin, small quantities of bradykinins and
serotonin.
1% of WBCs
Basophils
Basophils and mast cells play important role in allergic reactions.
IgE attached to surface of basophils and when antigen bind with
IgE on the surface, degranulation follows this binding and release
of histamine, bradykinin, serotonin, Slow Reactive Substance of
Anaphylaxis, heparin and other lysosomal enzymes
antigen
Lymphocytes
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Agranulocyte: does not contain visible granules in the cytoplasm.
Second most common WBCs 30%
Large round nucleus that fills most of the cytoplasm
Responsible for the specific immunity (Acquired immunity) bad cells/
antigens/foreign antigen
T cells come from PHSC and maturate in the thymus.
B cells originate from bone marrow PHSC and maturate in the liver
and bone marrow.
T lymphocytes called the cell-mediated immunity
B lymphocytes are known as humoral immunity because they produce
anti bodies from plasma cells.
Monocyte
Agranulocyte with pale-blue cytoplasm
Horse-shoe shaped nucleus or kidney shape
Immature in the blood stream, undergoes chemotaxis during inflammation
So it migrates from blood in to tissue spaces and enlarges their to become macrophage
Macrophage is a strong phagocyte, can phagocytize whole RBC, malarial parasites and
dead neutrophils
 has a very important function in the initiation of the specific immune system
Role of macrophages in activation of
lymphocytes
• When macrophage phagocytize invading microorganisms and
digest them, the antigenic products liberated into macrophage
cytoplasm. Macrophages pass these antigens directly to
lymphocytes leading to activation of specific lymphocytes that
can make proper immune reaction against invading
microorganism.
• Also macrophages produce substance (interleukin-1) that
stimulates growth and reproduction of specific lymphocytes.
bacteria
macrophage
lymphocyte
Monocyte-Macrophage Cell System
(Reticuloendothelial System)
 Mobile macrophages migrate from blood stream into tissue space and attack foreign
invaders.
 Another large portion become attached to the tissues and remains their for months or
even years until they are called to action
 These attached tissue macrophages have the same capabilities as mobile one, under
stimulation they can detach and again become mobile , phagocytizing many particles.
 The total combination of monocytes, mobile macrophages, fixed tissue macrophages,
and a few specialized endothelial cells in the bone marrow, spleen, and lymph nodes is
called the reticuloendothelial system or monocyte-macrophage system
Tissue Macrophages in the Skin and Subcutaneous
Tissues (Histiocytes).
Macrophages in the Lymph Nodes
Alveolar Macrophages in the Lungs.
Macrophages (Kupffer Cells) in the Liver Sinusoids.
Macrophages of the Spleen and Bone Marrow.
Macrophages in the brain are called micrglia