BLOOD and BONE MARROW
Nadia Goodwin ng2021
Missy Walker maw2106
OVERVIEW
PERIPHERAL BLOOD SMEARS:
only contains mature cells (no precursors)
cell types:

erythrocytes (RBCs)

platelets

leukocytes (WBCs)
 granulocytes: neutrophils, basophils, eosinophils
 agranulocytes: lymphocytes, monocytes (macrophages)
PERIPHERAL BLOOD SMEARS
1. erythrocyte
largest proportion of cells in the blood
biconcave discs (7-8 m)
lack nucleus and cellular organelles
cotains hemoglobin (carries O2 and CO2)
2. neutrophil (polymorphonuclear leukocyte, PMN)
50-70% of WBCs in peripheral blood
diameter = 10-12 m (larger than RBC)
3-5 lobed nucleus stains deep purple
pale cytoplasm
small, light purple granules

few azurophilic (1°) granules (myeloperoxidase, lysosomal enzymes)

many specific (2°) granules (lysozyme, collagenase)
function: acute inflammation (exit circulation to site of injury, phagocytose pathogen, granules fuse with phagosome to
destroy pathogen)
3. basophil
rare, hard to find (less than 1% of WBCs)
diameter = 8-14 m
lobulated nucleus, obscured by granules
dark blue specific granules of varying sizes

contain hydrolytic enzymes, heparin sulfate, histamine, slow reacting substance, SRS
act like tissue mast cells, bind antigen specific IgE, exposure to antigen releases vasoactive substances from granules,
leads to inflammation
4. eosinophil
2-4% of WBCs
diameter 10-14 m
bilobed nucleus
bright pink eosinophilic granules of uniform sizes

contain arginine rich major basic protein, peroxidase, histaminase, arylr-sulfatase
important in allergic reactions, parasitic infections, and phagocytosis of antibody-antigen complexes
5. monocytes
3-8% of WBCs
diameter 9-18 m (usually larger than PMN’s)
kidney shaped nucleus, less compact nucleus than PMN
pale, basophilic cytoplasm without specific granules, but do contain azurophilic lysosomes
exit circulation to tissues, differentiate into phagocytes (macrophage, osteoclast, alveolar macrophage, etc)
differentiated monocytes function in phagocytosis & antigen presentation to lymphocytes
6. lymphocytes
20-40% of WBCs
diameter = 6-12 m
intensely staining, round to oval nucleus; may be slightly indented
thin, pale blue rim of cytoplasm WITHOUT granules
B cells & T cells are indistinguishable

B cells: function in antibody production, carry Ig on plasma membrane which recognize antigen

T cells: function in cell mediated immunity, destroy virally infected cells, provide help to B cells
ERYTHROID SERIES
PROERYTHROBLAST
- relatively large cell 12-15m in diameter
- large, central, spherical nucleus with one or two nucleoli
- cytoplasm: moderately basophilic (blue) due to ribosomes
- look for an unstained region of cytoplasm=Golgi ghost
BASOPHILIC ERYTHROBLAST
- smaller than proerythroblast
- checkerboard nucleus (heterochromatic and smaller)
- intense basophilia (blue) due to lots of free ribosomes
POLYCHROMATOPHILIC ERYTHROBLAST
- smaller than basophilic erythroblast
- smaller intensely heterochromatic nucleus
- purple/lilac cytoplasm due to combo of basophilia from ribosomes and eosinophilia from increasing
amount of hemoglobin
- LAST MITOTIC STAGE
NORMOBLAST
- smaller than polychromatophilic erythroblast
- small, compact, intensely staining nucleus; getting ready to extrude the nucleus
- eosinophilic cytoplasm (abundant hemoglobin); NOTE: the color of a normoblast is close to the
normal pinkish color of the mature erythrocyte
RETICULOCYTE
- immature erythrocyte that still retains some basophilia due to the presence of RNA
- only seen with a special (supravital) stain on the peripheral smear
- increased # seen with anemia
ERYTHROCYTE
- smallest (7-8 m)
- NO NUCLEUS
- Acidophilic (pink)
TRENDS
Immature  Mature
Basophilic  Eosinophilic
Large euchromatic nuclei  heterochromatic  pyknotic  no nucleus
GRANULOCYTE SERIES
MYELOBLAST
- 15-20 μm
- large, euchromatic, spherical nucleus (>3nucleoli)
- basophilic cytoplasm with no granules
- prominent nucleoli
- can be seen in peripheral blood with certain leukemias
PROMYELOCYTE
- 18-24 μm
- Large nucleus
- **Golgi ghost**
- **azurophilic granules (purple) **
- CANNOT tell which type of granulocyte it will develop into
MYELOCYTE (Neutrophilic, Basophilic, or Eosinophilic)
- smaller
- eccentric, spherical nucleus
- ** granules specific to N,B,E appear**
- LAST MITOSIS
METAMYELOCYTE
- **indented, heart-shaped nucleus**
- many cell-specific granules
BAND CELL
- immature granulocyte
- U-shaped nucleus just prior to segmentation
- increased # seen with acute infections (a left shift)
MATURE GRANULOCYTE
- Neutrophil, Eosinophil, or Basophil
- Segmented nucleus
TRENDS:
Immature  Mature
Large cell  Small cell
No granules  Azurophilic (non-specific) granules  Cell-specific granules
Round nucleus  indented nucleus  U-shaped  multilobed (specific for cell type)
PLATELET PRECURSOR
MEGAKARYOCYTE
- HUGE compared to other cells
- Contain multi-lobed nucleus (as opposed to osteoclasts which are multinucleated)
- Platelets are formed by invaginations of the plasma membrane that fuse to form clefts that eventually
break off (Be sure to look at the EM!!)