MLAB 1415: HEMATOLOGYChapter 7: Leukocytes

Part Two

MONOCYTES

Monopoiesis - the production and development of monocytes, macrophages and their precursors. Monocytes are produced in the bone marrow.

MONOCYTES Differentiation & maturation

Produced from CFU-GMCan further differentiate into macrophages

in the tissues

LifespanP.B ~ 8 hoursTissue

RegulationProduction primarily regulated by cytokines

GM-CSF IL-3 M-CSF

MONOCYTES/MACROPHAGES

Function Protect the host from infectious agents or

pathogens via innate and adaptive immune response

Phagocytosis Scavengers

MATURATION OF THE MONOCYTIC SERIES

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 Promonocyte (difficult to discern)

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

Nucleus Round with chromatin creases or brain-like folding Central Reddish-purple with light clumping of chromatin 0-2 nucleoli

N:C ratio = 3:1 or 2:1

PROMONOCYTE

MATURATION OF THE MONOCYTIC SERIES Mature monocyte

Normal in circulation: 2-9% Size: 12-20µm Cytoplasm

Pale gray-blue and abundant Bleb-like pseudopods at periphery, variable shape Numerous fine pale red dustlike granule scattered throughout Vacuoles common

Nucleus Increased folding or elongated Central Purplish with finer clumped chromatin No nucleoli

N:C ratio = Variable

MONOCYTE

MONOCYTES…THINK….

Fine, Lacy Chromatin Ground Glass Cytoplasm

MACROPHAGES 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 alias’

Histiocytes in the loose connective tissue

Kupffer cells in the liverOsteoclasts in the boneMicroglial cells in the nervous

systemAlso 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/storyReade

r$1075 MacKenzie, S., & Lynne, W. J. (2010). Clinical

Laboratory Hematology. Upper Saddle River: Pearson Education, Inc.