Erythropoiesis Flashcards
Erythropoiesis
process of RBC formation
RBC survival determined by
labeling
the RBCs with
chromium-51 (51Cr),
normal rage of RBC survival det.
28 to 38 days
total mass of RBCs circulating in the peripheral blood AND the bone marrow RBC precursors
Erythron
a term that describes the dynamics of RBC creation and destruction
Erythrokinetics
mmature hematopoietic cells that is committed to a cell line but
CANNOT be identified morphologically
Progenitor cell
BFU-E, CFU-E
immature hematopoietic cell that is morphologically IDENTIFIABLE
as belonging to a given cell line
Precursor cells
EARLIEST marker of erythroid differentiation; transferrin receptor
CD71
primary target cells of EPO
BFU-E & CFU-E
3 major effects of EPO:
1.) allowing early release of reticulocytes from the bone marrow
2.) reducing the time needed for cells to mature in the bone marrow
3.) preventing apoptotic cell death (note: apoptosis rescue is the
MAJOR way in which EPO increases RBC mass)
primary cell source of EPO
Peritubular interstitial cells (kidneys)
GH is produced by
Anterior pituitary gland
GH function
stimulate erythropoiesis directly (BM)
testosterone function in erythropoiesis
stimulates indirectly
Prolactin produced by
Anterior pituitary gland
Prolactin function
stimulate erythropoiesis directly (BM)
estrogen effect on RBC count
lower
estrogen function
inhibits erythropoiesis
committed to eryhtroid progenitor cells
BFU-E & CFU-E
___ days for the BFU-E to mature to an erythrocyte
18 to 21 days
_____
are spent by BFU-Eas recognizable precursors in the bone marrow.
6 days
Retics found in Wright stain
Polychromatophilic Erythrocytes & Diffusely Basophilic Erythrocytes
rubriblast gives rise to ___ prorubricytes
2
earliest recognizable erythroid precursor using light microscope
Rubriblast
youngest of the precursor
Rubriblast
Rubriblast N:C ratio
8:1
nucleus takes up < 50%
lower ratio
nucleus takes up > 50%
ratio is higher
Prorubricyte N:C ratio
6:1
nucleoli in prorubricyte
0 to 1
The prorubricyte gives rise to
________ rubricytes
4
criteria in identifying prorubricyte from rubriblast
1) coarser chromatin
2) absence of nucleoli
last stage with nucleolus
prorubricyte
first stage of hemoglobinization (Hb synthesis)
prorubricyte
Each of this cell (rubricyte) gives
rise to ___________ metarubricytes
2
rubricyte is confused with
lymphocyte
lymphocyte vs. rubricyte
L:
N-crushed velvet
C: sky-blue (robin egg”
R:
N- Checkerboard
C: muddy gray
last stage capable of mitosis
rubricyte
diffusely
lilac in color
(muddy
or gray)
rubricyte
rubricyte N:C ratio
4:1
pyknotic nucleus
Metarubricyte/Orthochromatic normoblast/Late normoblast
Metarubricyte N:C ratio
1:2
Metarubricyte other names
Nucleated RBC,
Pyknotic erythroblast,
Acidophilic normoblast
salmon-pink
Metarubricyte
last stage with nucleus
Metarubricyte
Pyrenocytes contain
Howell-Jolly bodies
last stage of hemoglobin synthesis
Reticulocyte
polychromasia
Reticulocyte
Retics Spends ___ day/s in the bone marrow
2 to 3
retics spends ___ day/s in the Peripheral blood
1
Shift Cells
Polychromatophilic macrocytes
Polychromatophilic macrocytes/ shift cells seen in
cases of increased RBC production
Stress Reticulocytes
macroreticulocytes
Stress Reticulocytes seen in
more severe conditions like Hemolytic anemia
mature erythrocytes appearance
biconcave disk,
1.5 to 1.5 um thick,
7 to 8 um,
120 days lifespan,
or erythrocytes produced from each rubriblast
16
normal ratio of RBC:WBC
600:1
normal RBC:platelet ratio
15:1
measures RBC survival
Chromium-51
salmon-pink with central pallor occupying ___ the cell
1/3
RBC membrane constituents:
8% carbohydrates, 40% lipids, and 52% proteins
maintain membrane integrity
♦TRANSMEMBRANE PROTEINS
Glucose transporter, supports ABH antigens
Glut-1
Transports negatively charged sialic acid, supports MN
determinants
Glycophorin A
Transports negatively charged sialic acid, supports
Ss determinants
Glycophorin B
Transports negatively charged sialic acid, supports
Gerbich system determinants
Glycophorin C
shape and flexibility of the erythrocyte
♦SKELETAL PROTEINS
Primary cytoskeletal proteins
α-spectrin
β-spectrin
MCHC value of Hereditary Spherocytosis patient
35-38mg/dL
RBC in HS
stretchable but less elastic
most sensitive and specific test to confirm the diagnosis of HS
-EMA binding test
most
common form of stomatocytosis
Dehydrated hereditary
stomatocytosis
(Hereditary Xerocytosis)
mutations that change MEMBRANE STRUCTURE
1) Hereditary spherocytosis
2) Hereditary elliptocytosis/pyropoikilocytosis
3) Hereditary ovalocytosis (Southeast Asian ovalocytosis)
mutations that change MEMBRANE TRANSPORT PROTEINS
1) Overhydrated hereditary stomatocytosis
2) Dehydrated hereditary stomatocytosis or hereditary xerocytosis