144
UNIT 2
Basic Tissues
Figure 8-8.
Eosinophil in connective
tissue.
EM,
3
12,000
The irregular surface contours of this cell
suggest that it was in motion at the time
the specimen was obtained. The
two lobes
typical of the nucleus of an
eosinophil
are
present in the section, and the relatively
large speciF
c granules have the features
that are characteristic of eosinophilic gran-
ules. The proF
les of the granules have two-
dimensional shapes that are consistent with
a biconvex three-dimensional shape. Each
granule has a crystalline core (
internum
)
composed of a major basic protein, one
of the cationic proteins sequestered within
eosinophilic granules.
Internum (crystalloid)
Internum (crystalloid)
in eosinophilic granules
in eosinophilic granules
Internum (crystalloid)
in eosinophilic granules
Lobes of nucleus
Lobes of nucleus
Lobes of nucleus
Types of
Leukocytes
Approximate %
of WBCs
Nucleus
Granules in Cytoplasm
Main Functions
Lymphocyte
25%–33%
Round, relatively large
compared to cell size
If present, only a few azurophilic
granules
Play important role in
immune defense
Monocyte
3%–7%
Large, kidney shaped
or horseshoe shaped;
nonsegmented
Azurophilic granules only (lysozyme,
endogenous pyrogens/IL-1)
Phagocytosis of any
recognizable nonself
agents after becoming
mature tissue phagocytes
Neutrophil
54%–62%
Multilobed (F ve or
more);
segmented
Azurophilic (primary) granules
contain
lysosome, myeloperoxidase, and
superoxide; small, salmon-pink, speciF
c
( secondary) granules contain major
basic proteins, lactoferrin, lysozyme,
collagenase, and proteases
Defend against bacterial
and fungal infection
Eosinophil
1%–3%
two to three lobes;
segmented
Azurophilic granules; large red,
speciF c granules contain major basic
proteins, acid phosphatase, peroxidase,
arylsulfatase, and
β
-glucuronidase
Defend against
infection
by parasitic worms;
moderate infl ammation
in allergic reaction; F ght
viral infection
Basophil
<1%
two to three lobes;
segmented
Azurophilic granules; large violet (or
purple-blue), speciF c granules contain
histamine, heparin, peroxidase, eosino-
phil/neutrophil chemotactic factor
Involved with
infl ammation and
allergic reactions (similar
to mast cells)
TABLE 8-1
Leukocytes
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