This document summarizes the process of granulopoiesis, the production of granulocytes which are a type of white blood cell. It describes the stages that pluripotent stem cells go through to mature into granulocytes, including the primitive WBC, myeloblast, promyelocyte, myelocyte, and metamyelocyte stages where the cell size and nucleus change and cytoplasmic granules develop. The final stage is the mature granulocyte, mainly neutrophils. The production of granulocytes occurs exclusively in the bone marrow through extravascular processes between fat cells. Granulocyte levels are regulated by factors that stimulate or inhibit further release from the bone

1. Akansha kadam
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WBC
Formation and
Regulation
Akansha Kadam
Roll no. 21

2. 1. The process of development
and maturation of leukocyte
(WBC),is called leucopoiesis.
2. It is a part of Hematopoeisis
(formation of Blood cells).
3. All Blood cells develop from
Pluripotent Hematopoeitic stem
cells.
DEVELOPMENT OF
LEUCOCYTES (WBCs))

3. Granulopoiesis
• Production of white blood cells which
contain granules in their cytoplasm.
Lymphopoiesis
• Production of white blood cells which
does not contain granules in their
cytoplasm
Types of leucopoiesis

4. Granulopoiesis
Granulocytes develop mainly and exclusively in bone marrow.It is
wholly extravascular process. Between the fat cells of the marrow
there are branched reticulum cells .Reticulum cells multiply by mitosis
forming primitive WBCs

5. Stages of granulopoesis
STAGE CELL SIZE NUCLEUS CYTOPLASM MITOSIS
Primitive WBC 18-23
micrometer
Large, spherical,
many nucleoli
and open
chromatin
Basophilic, thin
rim of cytoplasm
all around the
nucleus
Mitosis present
1.

6. STAGE CELL SIZE NUCLEUS CYTOPLASM MITOSIS
Myeloblast 16-20
micrometer
Large, pale,
many nuceoli
fine stippled
chromatin
Amount
increases
narrow blue rim
without
granules
Mitosis present
and shows
active protein
synthesis
2.

7. 3.
STAGE CELL SIZE NUCLEUS CYTOPLASM MITOSIS
Pre- myelocyte 14-18
micrometer
Size decreases,
nucleoli
disappears and
chromatin
condenses
Amount
increases
further
Mitosis present

8. STAGE CELL SIZE NUCLEUS CYTOPLASM MITOSIS
Myelocyte
proper
12- 16
micrometer
Round, nucleus
size further
decreases
Amount
increases , less
basophilic,
granules
appears with
special staining
reactions
Multiplication is
maximum
4.

9. STAGE CELL SIZE NUCLEUS CYTOPLASM MITOSIS
metamyelocyte 10-14 micrometer Nucleus size
decreases
becomes
indented and
lobed
Amount further
increases and
becomes more
liquid, granules
show ameboid
movement
Mitosis stops here
Mature WBC
5.

11. (inhibits)
Granulopenia and
macrophages
Granulocyte
releasing factor
(GRF) and
granulopoietin
Stimulates bone
marrow
Mature
granulocyte
(mainly
neutrophils)
A factor which via
Negative
feedback
mechanism
release release
For every circulating granulocyte
,50-100 mature cells are held in
the bone marrow reserve.The
relative constancy of blood
granulocyte count is maintained
by an efficient feedback
mechanism by circulating factors.
Regulation of
granulopoesis

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