Granulocytes: Neutrophils Most numerous WBC in blood Multilobed nucleus Granules: –Azurophilic granules –Specific granules Function –1 st wave of cells in acute inflammation; can phagocytose bacteria
Granulocytes: Basophils Rare! Lobulated nucleus often obscured by granules Dark Blue Granules –Hydrolytic enzymes, heparin sulfate, histamine, SRS Function –Role in hypersensitivity and anaphylaxis
Granulocytes: Eosinophils Bilobed nucleus Bright pink Granules –Arginine rich major basic protein, peroxidase, histaminase, arylsulfatase Function: –Important in allergic rxns, parasitic infections, and phagocytosis of Ab-Ag complexes
Agranulocytes: Monocytes Largest WBCs in blood smear Migrate through blood to the tissues; once in tissues they differentiate into phagocytes (macrophages)
Agranulocytes: Lymphocytes About size of RBCs Function –Main functional cells of adaptive immune system –T cells –B cells
Questions Which of the following cell types would be expected to be increased in number with a bacterial infection? Viral? Parasitic?
RBC Development Watch for trends!
Proerythroblast Biggest in lineage Large central nucleus with one or two nucleoli Basophilic cytoplasm b/c ribosomes Look for Golgi ghost
Basophilic Erythroblast Smaller than proerythroblast Checkerboard nucleus (heterochromatic) Intense basophilia (lots of ribosomes!)
Proerythroblast vs Basophilic Erythroblast
Polychromatophilic Erythroblast Smaller than basophilic erythroblast Smaller intensely heterochromatic nucleus Purple/lilac cytoplasm mix of basophilia from ribosomes and growing eosinophilia from hemoglobin LAST MITOTIC STAGE!
Normoblast Smaller than polychromatophilic erythroblast Small, compact, intensely staining nucleus that is getting ready to be extruded Eosinophilic cytoplasm due to abundant hemoglobin
Reticulocyte Immature RBC that has polyribosomes Appear as polychrom- atophilic erythrocyte on blood smear When stained with a special (supravital) stain Reticulocyte
Erythrocyte Smallest Eosinophilic due to hemoglobin NO NUCLEUS!
Development of Granulocytes
What are the Granulocytes? These are cells of the immune system (White Blood Cells) that contain vesicles. The vesicle contents vary among cell lines and stain differently. Neutrophils (polymorphonuclear or PMN cells) Eosinophils Basophils
Trend of Development Larger to smaller Azure granules to specific granules Round nucleus to altered shape nucleus Granulocyte Lineage: Myeloblast → Promyelocyte → Myelocyte → Metamyelocyte → Band → Granulocyte (Erythroid: Proerythroblast →Basophilic erythroblast → Polychromatophilic erythroblast → Normoblast → Reticulocyte → Erythrocyte)
Myeloblast Prominent nucleoli
PROmyelocyte Details Golgi ghost Can’t distinguish type of granulocyte yet Eccentric nucleus Don’t confuse with proerythroblast or basophilic erythroblasts
Myelocyte Last stage in which mitosis can occur Begin to see who’s a neutrophil, who’s an eosinophil (who’s a basophil) Golgi ghost
Neutrophilic Myelocyte vs Eosinophilic Myelocyte
METAmyelocyte nucleus changing shape, not spherical Soooo... No more mitosis
Band Cell Immature granulocyte Elongated nucleus of nearly uniform width; horseshoe/U-shaped
Myeloblast – no granules capable of mitosis Promyelocyte – azurophilic granules Mylocyte – specific granules Metamylocyte – specifc granules nucleus changes shape Band cell – (PMN only) specific granules Mature Granulocyte – specific granules
Compare what you see...
Megakaryocyte Huge Platelets form from invaginations of this Multilobular nucleus