MLT 120 Exam I Flashcards by Alex Olsen

What controls the entrance and exit of substances into and out of blood cells?

Cell membrane

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Where is the main site of hematopoiesis?

In an adult?

Liver

Bone Marrow

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What is the major site of extramedullary hematopoiesis?

Spleen

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What three major criteria are used to identify blood cells?

Cell size, shape, ctyoplasm

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How is bone marrow cellularity determined?

The number of nucleated cells is compared to the total amount of cells and fat present

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What is the normal M:E ration?

2:1-4:1 average is 3:1

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How does a doctor use a bone marrow exam?

It aids in making definitive diagnosis
Management of pt and evaluation of treatment
Assessment of iron stores

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What is the dualistic theory of blood cell origin?

Granulocytes originate from nongranular marrow precursors, and lymphocytes originate from lymphoid tissue; dual origin of white blood cells

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What are the stages of RBC development from youngest to oldest and how does appearance change as it moves from stage to stage?

Rubriblast - youngest
prorubricyte
Rubricyte - start to see hgb
Metarubricyte - loss of nucleus
Reticulocyte
Erythrocyte

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What is the average life of a RBC?

100-120 days

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What is erythropoietin, where is it produced, and how is its secretion stimulated?

Mucoprotein, formed by the kidneys, that is capable of maintaining a normal RBC mass by stimulation of the bone marrow.

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Define apoferritin

an absorption protein that attaches to Fe2+ for absorption to occur

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Define ferritin

Submicroscopic iron

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Define hemosiderin

“conglomeration” of ferritin which can be seen microscopically

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Define transferrin

Transfer protein of oxidized iron; Fe3+

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When nucleus maturation lags behind the cytoplasm maturation

Asynchrony

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Nuclear fragmentation

Karyorrhexis

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How does the RBC count vary for physiological reasons and what are some conditions that cause it to vary?

normal body response to decrease oxygen or decrease plasma; dehydration, high altitudes, pulmonary or cardiac issues

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What are the characteristics of a good RBC diluent?

Isotonic to RBC; contain a fixative

How do you calculate a RBC count when it is performed on a hemocytometer?

Count four corners and center square on both sides; add count from both sides and multiple by 10,000

What is the structure of normal hemoglobin A?

two alpha and two beta polypeptide chains, and four iron containing heme groups

What pathway provides most of the energy for a mature RBC?

Emeden-Meyerhof Glycolytic Pathway

What pathway functions to protect hemoglobin from oxidation?

Hexose Monophosphate (HMP) Shunt

In order to function as an oxygen carrier, the iron in hemoglobin must be in what oxidation state?

Ferrous; Fe2+

What is the Sahli method of hemoglobin determination and to what molecule is hemoglobin converted in this method?

Acid hematin; Hgb F

What is the most commonly used method for hemoglobin determination in the modern hematology lab?

Cyanmethemoglobin

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 and how is it performed?

Hematocrit determination blood is collected in heparinized(red) capillary tubes, seal one end, spun in microhematocrit centrifuge to obtain optimal packing of cells

Name two methods for performing the Hct determination and indicate why one method is preferred over the other.

``` Macromethod of Wintrobe and Micromethod(preferred); simple procedure small sample simple equipment reproducible highly accurate can observe macroscopically can evaluate color of plasm and amount of buffy coat ```

What factors can cause an increased ESR? Decreased?

Increase; abnormal amounts of protein, i.e. fibrinogen, globulin Decrease; abnormal shape of RBC(sickle cell), polycythemia, spherocytosis

What is the "rule of three"?

3xRBC= Hbg; 3xHbg=Hct

What test is the most reliable assessment of the effective erythroid activity of the bone marrow?

Reticulocyte count

What is the normal reticulocyte count?

0. 5-2% but 1% is average norm | 2. 5%-6% in newborns

What stains are used for retic procedure?

New Methylene blue | Brilliant Cresyl Blue

How are retics observed on a Wright's stained smear?

polychromatophilc/polychromasia

What reagent is used for the sickle cell solubility test? | The slide test?

Solubility test- Sodium dithionite; reads turbidity, if lines can be seen through the tubes(=) or if they can't(+) Slide test- Sodium metabisulfite; read under the scope

What is the reagent used in the osmotic fragility test?q

Saline; dilutions of NaCl

How is the osmotic fragility test read?

read color of supernatant of spectrophotometer

What conditions cause an increased osmotic fragility? | Decreased?

Increased; hemolytic anemias, spherocytosis | Decreased; sickle cell, iron deficiency, thalassema, or where target cells can be found

Anisocytes Macrocytes Microcytes

Variation in size

Spherocytes Ovalcytes Elliptocytes Poikilocytes

Variation in Shape

Normochromic Hypchromic Polychromasia

Variation in color

Heinz bodies Howeel-Jolly bodies Cabot rings Pappenheimer bodies

Variation in Structure

According to their composition, what RBC inclusion should be counted in a reticulocyte count?

Basophilic Stippling

``` What is the chemical composition of: basophilic stippling Heinz bodies Howell-Jolly bodies Pappenheimer bodies ```

RNA denatured Hgb DNA Iron