CHAPTER 8
Blood and Hemopoiesis
151
Figure 8-14A.
Promyelocytes, bone marrow smear
. Wright
stain,
3
710; inset
3
1,569
Promyelocytes
(also called
progranulocytes
) have a round
or oval-shaped nucleus with one to three nucleoli. The cyto-
plasm is light blue, containing some dark purple granules
(
azurophilic granules
). At this stage, specif
c granules have
not been produced. Promyelocytes vary in size and are pro-
duced by the division oF
myeloblasts
. Their nuclei have a
smooth, f
ne texture because oF the Fact that most oF the
chromatin is
euchromatin
, which is delicately dispersed.
Promyelocytes
divide to Form
myelocytes
.
D. Cui
Promyelocyte
Promyelocyte
Promyelocyte
Promyelocyte
Promyelocyte
Promyelocyte
Promyelocyte
A
D. Cui
D. Cui
Neutrophilic
Neutrophilic
myelocyte
myelocyte
Neutrophilic
Neutrophilic
myelocyte
myelocyte
Eosinophilic
Eosinophilic
myelocyte
myelocyte
Eosinophilic
Eosinophilic
myelocyte
myelocyte
Neutrophilic
myelocyte
Neutrophilic
myelocyte
Eosinophilic
myelocyte
Eosinophilic
myelocyte
Neutrophilic myelocyte
Eosinophilic myelocyte
B
Figure 8-14B.
Myelocytes, bone marrow smear.
Wright
stain,
3
710; inset
3
1,569
The
myelocyte
has an oval or kidney-shaped nucleus that
has no nuclei and a coarse texture because oF increasing
heterochromatin content. The cytoplasm contains
azuro-
philic granules
and
specif
c granules
. In this stage, the cell
has stopped producing azurophilic granules. In addition,
these granules have also been diluted during cell division,
so they are not as prominent as in the promyelocyte stage.
At the same time, the cell has begun to make and accumu-
late specif
c granules so that the cytoplasm starts to take
the characteristic appearance oF a mature granulocyte. The
specif
c granules in neutrophilic myelocytes are small and
appear pinkish, granules in eosinophilic myelocytes are large
and stain red, and granules in basophilic myelocytes are
blue-purple. Basophilic myelocytes are least numerous and,
thereFore, diFf
cult to f
nd. In general, myelocytes are smaller
than promyelocytes, and their nuclear shape and size may
vary. This stage is the longest in
granulocytopoiesis
.
D. Cui
Eosinophilic
Eosinophilic
metamyelocyte
metamyelocyte
Neutrophilic
Neutrophilic
metamyelocyte
metamyelocyte
Neutrophilic
Neutrophilic
metamyelocyte
metamyelocyte
Eosinophilic
Eosinophilic
metamyelocyte
metamyelocyte
Eosinophilic
metamyelocyte
Eosinophilic
metamyelocyte
Neutrophilic
metamyelocyte
Neutrophilic
metamyelocyte
Neutrophilic
metamyelocyte
C
Figure 8-14C.
Metamyelocytes, bone marrow smear.
Wright stain,
3
710; inset
3
1,569
Metamyelocytes
are small cells. They have condensed
nuclei, which are elongated with various degrees oF inden-
tation and contain clumped chromatin. Metamyelocytes
are unable to divide (myelocytes are the last stage in cell
division). The cytoplasm oF metamyelocytes contains both
types oF granules. Their cytoplasm and granules are similar
to those oF mature granulocytes. At this stage, cells have
their disting
u
ishing Features, but their nuclei have not yet
become segmented.
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