1. Leukocytes- The Monocytes Part Two
MLAB 1415: Hematology
Leukocytes- The Monocytes
Part Two

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

3. MONOCYTES 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

4. Monocytes/Macrophages
Function
Protect the host from infectious agents or pathogens via innate and adaptive immune response
Phagocytosis
Scavengers

5. 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

6. 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 delicate chromatin
Brain-like folding or indentation
Central
Reddish-purple with light clumping of chromatin
1-2 nucleoli
N:C ratio = 3:1 or 2:1

7. Promonocyte

8. 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 “lacelike”
No nucleoli
N:C ratio = Variable

9. Monocyte

10. Monocytes…THINK….
Fine, Lacy Chromatin
Ground Glass Cytoplasm

11. 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

12. Macrophages in Various Tissues
Macrophage 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)

13. Macrophage

14. References http://winsorb.com/silica-gel.php75
MacKenzie, S., & Lynne, W. J. (2010). Clinical Laboratory Hematology. Upper Saddle River: Pearson Education, Inc.