exam 1 Flashcards
what controls the entrance and exit of substances into and out of blood cells?
cell membrane
where is the main site of hematopoiesis in the fetus?
liver
where is the main site of hematopoiesis in the adult?
bone marrow
what is the major site of extramedullary hematopoiesis?
spleen
what three major criteria are used to identify blood cells?
size
shape of nucleus
appearance of cytoplasm
how is bone marrow cellularity determined?
by comparing nucleated cells to total amount of cells and fat present
what is the normal M:E ratio ?
between 2:1 - 4:1
average 3:1
how does a doctor use a bone marrow exam?
aid in making definitive diagnosis,
management of patient and evaluation of treatment,
assessment of iron stores
what is the dualistic theory of blood cell origin?
granulocytes and all other WBC’s develop from on precursor and lymphocytes develop from another
rubriblast (proerythroblast, pronormoblast)
youngest cell nucleus present fine chromatin present cytoplasm 14-24 micrometers
prorubricyte (Basophilic normoblast/ basophilic erythroblast)
12-17 micrometers
coarser chromatin and nucleoli than rubriblast
Rubrictye (polychromatic normoblast/ polychromatic erythroblast)
1st stage of visible hemoglobin production
10-15 micro meters
more cytoplasm and smaller nucleus than prorubricyte
Metarubricyte ( orthochromic normoblast / orthochromic erythroblast)
stage that the nucleus is lost
8-12 micrometers
reticulocyte (polychromatic erythrocyte/ diffusely basophilic erythrocyte )
8-10 micrometers
RNA present
erythrocyte
7-8 micrometers
pink color
what is the average life of a RBC?
100-120 days
what is erythropoietin?
a mucoprotein
where is erythropoietin produced?
kidneys
how is erythropoietin secretion stimulated?
stimulation in bone marrow in response to tissue hypoxia
apoferritin
a protein that ferrous iron (Fe2+) can bind too if not absorbed by the small intestine
ferritin
submicroscopic iron
hemosiderin
“conglomeration” of ferritin which can be seen with a microscope
transferrin
a protein that aids in transportation (along with oxidation) of iron to the bone marrow
what is asynchrony?
nuclear maturation and cytoplasmic maturation are not correct (not at same rate)
what is karyorrhexis?
nuclear fragments
how does the RBC count vary for physiological reasons ?
because of the normal response to decreased oxygen and decreased plasma
what are some physiological conditions that can cause the RBC count to vary?
high altitudes
obstructed pulmonary disease
pulmonary cardiac disease
polycythemia vera
what are the characteristics of a good RBC diluent?
isotonic to the RBC
prevents lysis and crenation to preserve original morphology and prevent clumping
how do you calculate a RBC count when it is performed on a hemocytometer
add both sides of the meter and then divide by 10,000
what is the structure of normal hemoglobin A?
2 alpha and 2 beta polypeptide chains
4 iron containing heme groups
what pathway provides most of the energy for a mature RBC
emden-meyerhof glycolytic pathway
in order to function as an oxygen carrier, the iron in hemoglobin must be in what oxidation state?
Fe 2+
what is the Sahli method of hemoglobin determination and to what molecule is hemoglobin converted to in this method?
acid hematin
what is the most commonly used method for hemoglobin determination in the modern hematology lab?
cyan methemoglobin
what hemoglobin pigment can not be converted to oxyhemoglobin?
sulfhemoglobin
which manual hematology procedure is the most reliable and reproducible?
hematocrit
what test measures the percentage of the RBC volume of whole blood?
hematocrit
how is the hematocrit test performed?
a capillary tube is filled 1/2 - 1/3 full with either venous or capillary blood
one end of the tube is sealed with clay and then spun on the special hematocrit centrifuge for 3-5 minutes at 12,000 rpms
the tube is then placed on a hematocrit reading device and then you have your results
what are two methods of the hematocrit test?
macromethod of wintrobe
micromethod
which of the two methods of the hematocrit test is preferred?
micromethod because it's a simple process, small samples of blood are used simple equipment is used reproducible very accurate
what test measures the “suspension stability” or RBC’s?
erythrocyte sed. rate
name two methods used for the ESR
wintrobe-landesburg
westergren
which method for the ESR uses a saline dilution and why?
westergren;
because diluting the blood offsets any anemia effects
what factors can cause an increased ESR?
bacterial infections
what factors can decrease an ESR?
polycythemia, SCA, spherocytosis
what is the “rule of three”?
an internal check on values given from instrument
3 X RBC = hgb
3 X hgb = hct
what test is the most reliable assessment of the effective erythroid activity of the bone marrow?
reticulocyte counts
what is the normal reticulocyte count ?
Adults: 0.5-2.0 %
what stains are used in the reticulocyte count?
1% Newmethylene blue
brilliant cresyl blue
supravital stains
how are retics observed on a wright’s stained smear?
the RNA and organelles precipitate from dye formaing a filamentous network of reticulum
polychromatophilic or polychromasia
what reagent is used for the sickle cell solubility test?
sodium dithianite
what reagent is used for the slide test?
sodium metabisulfate
how is the slide test and sickle cell solubility test read?
slide test is read by a microscope
the solubility test is read by ability to see lines behind tube or not
what is the reagent used in the osmotic fragility test?
saline (NaCl)
how is the osmotic fragility test read?
by reading the color of the supernatant of spectrophotometer
what conditions cause an increased osmotic fragility?
hereditary spherocytosis
hemolytic anemias
what conditions can cause a decrease in osmotic fragility?
sickle cell anemia
any conditions with target cells or thalessemia
what chemical composition do basophilic stipplings have?
RNA
what chemical composition do Heinz bodies have?
denatured hgb
what chemical composition do Howell-Jolly bodies have?
DNA
what chemical composition do pappenheimer bodies have?
iron
according to their composition, which abnormal RBC should be counted as reticulum in a reticulocyte count?
basophilic stipplings
