Upload
peanadss
View
222
Download
0
Embed Size (px)
Citation preview
8/17/2019 06. White Blood Cells
1/18
1
White Blood Cells
(Leukocytes)
8/17/2019 06. White Blood Cells
2/18
2
White Blood Cells (Leukocytes)
• Leukocytes (White blood cells or WBCs) are
the mobile units of the body’s immune defense
system
• Immunity is the body’s ability to resist or
eliminate potentially harmful foreign materials
or abnormal cells
8/17/2019 06. White Blood Cells
3/18
!
"he #unction of WBCs
• "he leukocytes and their deri$ati$es
1 %efend against in$asion by pathogens
(disease & causing micro'organisms such
as bacteria and $iruses) by phagocytiing
the foreigners or causing their destruction
by more subtle means
2 dentify and destroy cancer cells thatarise *ithin the body
8/17/2019 06. White Blood Cells
4/18
+
! #unction as a ,cleanup cre*- that
remo$es the body’s ,litter- by
phagocytiing debris resulting from dead
or in.ured cells
• "he latter is essential for *ound healing
and tissue rapair
8/17/2019 06. White Blood Cells
5/18
/
"here are fi$e types of leukocytes
• Leukocytes lack hemoglobin (in contrast to
erythrocytes) so they are colorless that is0
,*hite- unless specifically stained for
microscopic $isibility • "here are fi$e different types of circulating
leukocytes0 "he fi$e types of leukocytes fall
into t*o main categories
8/17/2019 06. White Blood Cells
6/18
& %epending on the appearance of their nuclei
& "he presence or absence of granules in theircytoplasm *hen $ie*ed microscopically
(#igure !)
& eutrophils0 eosinophils0 and basophils are
categoried as polymorphonuclear (,manyshaped nucleus-) granulocytes (3granule
containing cells-)
& "heir nuclei are segmented into se$eral lobesof $arying shapes0 and their cytoplasm
contains an abundance of membrane
enclosed granules
8/17/2019 06. White Blood Cells
7/18
4
• "he three types of granulocytes are
distinguished or the basis of the $arying affinity
of their granules for dyes5
& 6osinophils ha$e an affinity for the red dye
eosin0
& Basophils preferentially take up a basic bluedye
& eutrophils are neutral0 sho*ing no dye
preference
8/17/2019 06. White Blood Cells
8/18
7
• 8onocytes and lymphocytes are kno*n as
mononuclear (,single nucleus-) agranulocytes
(3cells lacking granules-)
& Monocytes are the larger of the t*o and ha$e
an o$al or kidney shaped nucleus & Lymphocytes, the smallest of the leukocytes0
characteristically ha$e a large spherical
nucleus that occupies most of the cell
8/17/2019 06. White Blood Cells
9/18
9
Figure 3. Normal blood cellular elements
8/17/2019 06. White Blood Cells
10/18
1:
Figure
8/17/2019 06. White Blood Cells
11/18
11
!"#N$L%&%I'I
• ;ranulopoiesis (or granulocytopoiesis) is
hematopoiesis of granulocytes "he blood
granulocytes and monocytes are formed in
the bone marro* from a common precursorcell (figure /)
8/17/2019 06. White Blood Cells
12/18
12Figure
8/17/2019 06. White Blood Cells
13/18
1!
Control o* granulopoiesis+ myeloid gro,th
*actors
• "he granulocytes series arises from bone
marro* progenitor cells *hich are increasingly
specialied
& 8any gro*th factors are in$ol$ed in thismaturation process including interleukin'1 (L'
1)0 L'!0 L'/ (for eosinophils)0 L'0 L'110
granulocyte macrophag colony'stimulating
factor (;8'C
8/17/2019 06. White Blood Cells
14/18
1+
-he *unction o* granulocytes
1 Chemota=is (Cell mobiliation and migration)
• "he phagocyte is attracted to bacteria or the
site of inflammation
• by chemotactic substances released fromdamaged tissues
• by complement components also
• by the interaction of leukocyte adhesionmolecules *ith ligands on the damaged
tissues
8/17/2019 06. White Blood Cells
15/18
1/
2 >hagocytosis
• ?ecognition of a foreign particle is aided by
opsoniation *ith immunoglobulin orcomplement (both neutrophils andmonocytes ha$e #c and C!b receptors)
! @illing and digestion
A=ygen'dependent and o=ygen'independentpath*ays
n the o=ygen'dependent reactions5
•
8/17/2019 06. White Blood Cells
16/18
1
& n neutrophilsm
• 2A2 reacts *ith myelopero=idase to killbacteria
• Dcti$ated o=ygen may also be in$ol$es a
fall in p *ithin phagocytic $acuoles into
*hich lysosomal anymes are released
• Lactoferrin & an iron binding protein present
in neutrophil granules & is bacteriostatic by
depri$ing bacteria of iron
8/17/2019 06. White Blood Cells
17/18
14
& n the o=ygen'independent
• Dlthough more than t*o doen factors
ha$e been implicated in control of themacrophages response to inflammation0
fi$e of these are belie$ed to play dominant
roles
• "hey are consist of 5
1. tumor necrosis factor ("#)0
2. interleukin-1 (IL-1),
3. granulocyte-monocyte colony stimulating factor(;8'C
8/17/2019 06. White Blood Cells
18/18
17
• "hese factors are formed by acti$ated
macrophage cells in the inflametd tissues and
• n smaller Euantities by other inflamed tissue
cells