Transcript Leukocytes- The Monocytes

MLAB 1415: HEMATOLOGY
Leukocytes- The Monocytes
Part Two
MONOCYTES
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Monopoiesis - the production and development
of monocytes, macrophages and their precursors.
Monocytes are produced in the bone marrow.
MONOCYTES
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Differentiation & maturation
 Produced from CFU-GM
 Can further differentiate into macrophages in
the tissues
Lifespan
 P.B ~ 30 hours
 Tissue
Regulation
 Production primarily regulated by cytokines
GM-CSF
 IL-3
 M-CSF
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MONOCYTES/MACROPHAGES
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Function
Protect the host from infectious agents or pathogens
via innate and adaptive immune response
 Phagocytosis
 Scavengers
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MATURATION OF THE MONOCYTIC SERIES
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Monoblast
 Size: 12-20µm
 Cytoplasm
 Blue, moderate amount
 No granules
 Nucleus
 Round, oval or slightly folded
 Eccentric
 Reddish-purple
 Chromatin fine and lacy
 Vacuoles may be present
 1-2 nucleoli
 N:C ratio = 4:1
MATURATION OF THE MONOCYTIC SERIES
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Promonocyte (difficult to discern)
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Size: 12-20µm
Cytoplasm
Paler gray-blue and abundant
 “Bleb-like” pseudopods at periphery
 May contain fine red “dust-like” particles, azurophilic
granules
 Vacuoles may be present
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Nucleus
Round with delicate chromatin
 Brain-like folding or indentation
 Central
 Reddish-purple with light clumping of chromatin
 1-2 nucleoli
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N:C ratio = 3:1 or 2:1
PROMONOCYTE
MATURATION OF THE MONOCYTIC SERIES
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Mature monocyte
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Normal in circulation: 2-9%
Size: 12-20µm
Cytoplasm
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Nucleus
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Pale gray-blue and abundant
Bleb-like pseudopods at periphery, variable shape
Numerous fine pale red dustlike granule scattered throughout
Vacuoles common
Increased folding or elongated
Central
Purplish with finer clumped chromatin “lacelike”
No nucleoli
N:C ratio = Variable
MONOCYTE
MONOCYTES…THINK….
Fine, Lacy Chromatin
Ground Glass Cytoplasm
MACROPHAGES
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Once the monocyte enters the tissues, it becomes
a macrophage
 Size:15-80µm
 Cytoplasm
 Gray-blue and abundant
 Ragged edges
 Vacuoles common
 Nucleus
 Round with netlike appearance
 Purplish with finer clumped chromatin
 Nucleoli appear
MACROPHAGES IN VARIOUS TISSUES
 Macrophage
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alias’
Histiocytes in the loose connective
tissue
Kupffer cells in the liver
Osteoclasts in the bone
Microglial cells in the nervous system
Also scattered throughout the body in
all organ tissues (spleen, lung,
abdomen, etc)
MACROPHAGE
REFERENCES
http://winsorb.com/silica-gel.php
 http://image.bloodline.net/stories/storyReader$10
75
 MacKenzie, S., & Lynne, W. J. (2010). Clinical
Laboratory Hematology. Upper Saddle River:
Pearson Education, Inc.
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