Hematopoiesis And Blood Cell Morphology Flashcards
What is hematopoiesis?
Process by which new blood cells are formed
Where are the sites of hematopoiesis ?
3rd week of gestation= yolk sac
Weeks later= AGM region
2-3 months through 6-7 months= liver
7 months through childhood,adult life= bone marrow
What is the difference in hematopoiesis in infancy,childhood and in puberty and adulthood?
In infancy and childhood all marrow is hematopoietic
In puberty and adulthood hematopoiesis is restricted to central skeleton and proximal ends of long bones
What is the normal cellularity?
100-age +/- 20%
What are the cells of hematopoiesis ?
Hematopoietic stem cells(HSC)- pluripotent, unrecognizable, express CD34
Multilineage progenitor cells- multipotent, unrecognizable, express CD34
Progenitor cells- unrecognizable, express CD34 and HLA-DR, irreversibly committed to single lineage
Blast cells- first recognizable, variable expression of CD34
Everything after blasts- recognizable, do not express CD34
What are the cells of granulopoiesis?
Myeloblast- non granular cytoplasm Promyelocyte- larger than blasts, granules present Myelocyte- specific granules evident Metamyelocyte- rarely seen Band cells-horse shoe shape
Under what circumstances are monoblasts and promonocytes increased?
In myeloid neoplasms
Not seen in appreciable numbers in bone marrow under normal conditions
What is the contraindication to bone marrow examination ?
Failure to meet appropriate indication criteria is the only major contraindication
Where is the site for bone marrow examination?
Posterior iliac crest
If not available anterior iliac crest
What is the uses of bone marrow biopsy?
Determine architectural relationships
Normal cellularity
What are the uses of bone marrow aspirate?
Cell counts
Cytologic evaluation of individual cells
Special studies:flow cytometry, cytochemistry
What are the abnormalities of erythrocytes based on size?
Microcytic hypochromic<7microns and pale(<80 fl)- seen in iron deficiency, anemia of chronic disease
Macrocytic cells >8.5 microns (100 fl)- seen in B12 or folate deficiency
What are the abnormalities of erythrocytes based on shape?
Spherocytes- lost of biconcave shape
Elliptocytosis/Ovalocytosis
Target cells-large floppy cells with redundant cytoplasmic membrane
Acanthocytes-amoeboid cells with unevenly distributed spicules
Echinocytes- evenly distributed spicules
Stomatocytes- mouth cells associated with alcoholic liver disease
Schistocytes- RBC fragments
Sickle cells -collapsed red cells
What are the morphologic features of hemoglobin C disease?
Irregularly contracted cells
Target cells
Hemoglobin C crystals
Spherocytes
What are the characteristics of Bite cell?
Appearance of bite taken out of cell
Heinz bodies seen on methylene blue stain
Associated with G6PDH deficiency
