Module 2: Normal Leukocytes (Monocytes/macrophages) Flashcards
where do monocytes develop
bone marrow
stages of monocyte development (3)
monoblast
promonocyte
monocyte
monocytosis
increased monocyte count
monoblast characteristics
nucleus round, oval, slightly folded, fine thread-like red-purple chromatin, up to 5 nucleoli
Cytoplasm basophilic with grey coloration, no granules
promonocyte characteristics
nucleus folded, convoluted with red-purple chromatin, 0-5 nucleoli
cytoplasm is abundant, blue-grey, often has pseudopods and vacuoles
monocyte characteristics
nucleus indented, lacy chromatin
Cytoplasm abundant with very fine granules (frosted appearance) pseudopods and vacuoles common
normal rel%
2-9% in adults
higher in newborns and young infants
how long do monocytes circulate before moving to tissue
36hrs
monocyte
immature cell in blood circulation
macrophage
mature cell in tissue
Produce more lysozyme, increase in size
May be fixed or motile
Mononuclear phagocyte system (MPS)
another term for reticuloendothelial system (RE cells)
common name: macrophages
functions of macrophages (4)
phagocytic response to foreign antigens
immune recognition
iron metabolism
preservation of a youthful and healthy population of blood cells
Phagocytic response to foreign antigens
responds chemotactivally to inflammation, phagocytose and kill ingested microorganisms
Neutrophils provide first wave, then macrophages phagocytose dead neutrophils and body tissue
activation by cytokines from CD4 T cells (often INF-y)
activated macrophage gets bigger, stickier, aggressive
form folds in membrane to catch more antigens
secretes monokines (IL-1)
If any antigens survive lysozyme fusion
the organism is isolated and impounded inside Langhans giant cell granulomas
Formed by fusing together of many macrophages
“walls off” the harmful substance
often occurs in TB
How is activation of macrophages suppressed
secretion of prostaglandin E2 (PGE 2) from T4 cells and from macrophages themselves
Immune recognition
macrophages act as antigen presenting cells (APC) where they bind, engulf, digest, make antigen immunogenic and then present the processed antigen in association with HLA-D antigens on its membrane surface to T4 (CD4) and B lymphs for recognition
IL-1
Interleukin 1
best known monokine
essential in activation of CD4T cells by foreign antigens
stimulates hepatocytes to secrete acute phase proteins
stimulates GM-CSF production by other macrophages
Acts as endogenous pyrogen in inflammatory response
Secretory effector cells (functions of mono/macro secretions)
removal of old blood cells
stimulation of self-defense against tumor cells
modulation of immune function
regulation of hematopoiesis
stimulation of inflammatory reactions
removal of infection organisms by phagocytosis
Iron metabolism/ preserving healthy blood
removal of dead, defective, aged blood/tissue cells, denatured plasma proteins, lipids, activated coagulation factors and antigen-antibody complexes
SPLEEN AND LIVER SINUSOIDS
phagocytose and digest cells, retaining useful components
