blood II Flashcards
where is the site of hematopoiesis
red bone marrow in the flat bones of the body
what bones are considered the flat bones of the body?
sternum vertebrae ribs clavicles bones of pelvis bones of skull
what is the function of hematopoietic stem cell niches
nurture stem cells and maintain their properties
facilitate activity of stem cells
where are stem cell niches found?
in association with spongy bone
what condition can result from alterations in stem cell niches?
preleukemic condition
what is the function of yellow bone marrow?
store reserve energy
reserve for hematopoietic tissue
describe nucleus of a blast
large and euchromatic
several nucleoli can be seen
large nucleo:cytoplasmic ratio
describe the cytoplasm of a blast
will appear pale blue
number ribosomes present
NO granules
as erthrocytes go through differentiation, what are the 4 changes the nucleus goes through?
decrease in size
chromatin becomes more heterochromatic
nucleoli will disappear
extrusion of the nucleus
as erthrocytes go through differentiation, what are the 4 changes the cytoplasm goes through?
decrease in basophilia (# of polysomes decrease)
increase in acidophilia (because Hb is becoming present)
what are the 7 cell types (in order) of erthrocytes?
blast basophilic erythroblast polychromatophilic erythroblast normoblast reticulocyte, orthochromatic erthyroblast mature RBC
describe basophilic erythroblast nucleus
nucleoli disappeared
checkerboard appearance of chromatin
color or basophilic erythroblast cytoplasm
basophilic
navy blue
what is the duration of the basophilic erythroblast stage
1-2 days
capable of 1-2 mitotic divisions
describe cytoplasm of a polychromatophilic erythroblast
gradual shift from intense basophilia to intense acidophilia due to increase of Hb and decrease of polysomes
Hb binds anionic dye eosin
RNA of ribosome binds cationic dye methylene blue
“double staining” reaction
duration of polychromatophilic erythroblast stage
3 days
capable of about 3-4 mitotic divisions
describe nucleus of a normoblast
no longer capable of mitosis
smaller than polychromataphilic erythroblast
totally heterchromatic
color or normoblast cytoplasm
mostly pink (with hint of blue) lots of Hb present and few ribosomes left
describe a reticulocyte
extruded its nucleus but still has a few cytoplasmic ribosomes (which can be stained blue)
make up about 1% of the circulating blood
orthochromatic erythroblast
lose residual RNA before they exclude nucleus (so still has it in this stage)
bright eosinophilic cytoplasm
color of eosiniphillic stain`
pink
how long does erythrocyte production take
8-9 days
where is the hormone erythropoietin synthesized?
kidney cortex
what is the function of erythropoietin?
increase rate of mitosis in developing RBCs
increase RNA synthesis in developing RBCs
