Exam 1 Flashcards
What controls the entrance and exit of substances into and out of blood cells?
cell membrane
Where is the main site hematopoiesis in the fetus?
liver
Where is the main site of hematopoiesis in the adult?
bone marrow (medullary)
What is the major site of extra medullary hematopoiesis?
spleen
What three major criteria are used to identify blood cells?
size, shape of the nucleus, appearance of the cytoplasm
How is bone marrow cellularity determined?
number of nucleated blood cells to the total number of cells and fat
What is the normal M:E ratio?
between 2:1 and 4:1, average 3:1
How does a doctor use a bone marrow exam?
aids in making a definitive diagnosis, evaluation of treatment, and assessment of iron stores
What is the dualistic theory of blood cell origin?
dual origin of white blood cells; granulocytes originate from non-granular marrow precursors and lymphocytes originate from lymphoid tissue
What are the stages of RBC development from youngest to oldest?
Rubriblast > rubricyte > metarubricyte > reticulocyte > erythrocyte
What is the average life of a RBC?
100-120 days
What is erythropoietin?
mucoprotein capable of maintaining normal RBC mass
Where is erythropoietin produced?
kidneys
How is secretion of erythropoietin stimulated?
bone marrow is stimulated in response to tissue hypoxia
Define apoferritin
protein that is necessary for absorption of iron to occur
Define ferritin
submicroscopic iron
Define hemosiderin
conglomeration of ferritin, which can be seen with a microscope
Define transferrin
protein that transports iron
What is asynchrony?
nuclear maturation lags behind the cytoplasm maturation
What is karyorrhexis?
fragmentation of nuclear chromatin
What are some conditions that cause RBC count to vary?
high altitudes, obstructive pulmonary disease, congestive heart failure
What are the characteristics of a good RBC diluent?
isotonic, contain a fixative to preserve shape of the RBC, prevent clumping, and have proper specific gravity
How do you calculate a RBC count when it is performed on a hemocytometer?
average of the two sides then multiplied by 10,000 because it is a 1:200 dilution
What is the structure of normal hemoglobin A?
two alpha and two beta chains
What pathway provides the most energy for a mature RBC?
Emden-Meyerhof Glycolytic Pathway
What pathway functions to protect hemoglobin from oxidation?
Hexose-mannose phosphate shunt (HMP shunt)
Iron in hemoglobin must be in what oxidation state to function as an oxygen carrier?
Fe2+
What molecule is hemoglobin converted to in the Sahli method of hemoglobin determination?
acid hematin
What is the most commonly used method for hemoglobin determination in the modern hematology lab?
Cyanmethemoglobin method
What hemoglobin pigment cannot 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?
height of the RBC compared to the height of the cells and the plasma
Two methods for performing hematocrit
Wintrobe and the micro method
What method is preferred for performing hematocrit?
micro method
Why is the micro method preferred over the Wintrobe method for finding the hematocrit?
simple and most reproducible, takes a small amount of blood and does not need any special equipment besides the centrifuge
What test measures the “suspension stability” of RBCs?
erythrocyte sedimentation rate
Name two methods used for the ESR
wintrobe-landesburg and Westergren method
Which method used to find ESR uses saline?
Westergren
Why is saline used in the Westergren method of calculating ESR?
believed to offset any effect of anemia
What factors can cause an increased ESR?
abnormal amounts of fibrinogen or globulins, bacterial infections, multiple myeloma, macroglobulinemia
What factors can cause a decreased ESR?
sickle cell anemia, spherocytosis, polycythemia
equation for MCV
(Hct / RBC) * 10
equation of MCH
(Hgb / RBC) * 10
equation for MCHC
(Hgb / Hct) * 100
What is the rule of three?
three times the RBC is the hemoglobin and three times the hemoglobin is the hematocrit
What test is the most reliable assessment of the effective erythroid activity of the bone marrow?
reticulocyte count
What is the normal reticulocyte count for an adult?
about 1%
What stains are used for a reticulocyte count?
supravital stains: new methylene blue, and brilliant crassly blue
How are reticulocytes observed on a wright’s stained smear?
polychromatophilic
What reagent is used for the sickle cell solubility test?
sodium dithionite
What reagent is used for the slide test?
sodium metabisulfite
How is the solubility test read?
tube is held one inch from the lined reader scale
What constitutes a negative solubility test?
if the lines can be seen
How is the slide test read?
checking for the appearance of sickle cells or “holly-leaf’ forms under the microscope
What is the reagent used in the osmotic fragility test?
saline
How is the osmotic fragility test read?
read the color of the supernatant on the spectrophotometer
What conditions cause an increased osmotic fragility?
some acquired hemolytic anemias, spherocytosis
What conditions cause a decreased osmotic fragility?
target cells, thalassemia, Hgb C, sickle cell anemia
What type of RBCs are placed into the structure category?
Howell-Jolly bodies, cabot rings, basophilic stippling, Heinz bodies, Pappenheimer bodies
What type of RBCs are placed into the size category?
macrocytes, anisocytes, microcytes
What type of RBCs are placed into the shape category?
sickle cell anemia, schistocytes, ovalocytes, elliptocytes, blister cells
What are the different categories that RBCs can be placed into based on color?
hypochromia and polychromia
What is the chemical composition of basophilic stippling?
RNA
What is the chemical composition of Heinz bodies?
denatured hemoglobin
What is the chemical composition of Howell-Jolly bodies?
DNA
What is the chemical composition of Pappenheimer bodies?
Iron
Which abnormal RBC can be counted as a reticulocyte?
basophilic stippling
