Clinical Laboratory Hematology 3rd Edition by McKenzie - Test Bank

Clinical Laboratory Hematology 3rd Edition by McKenzie – Test Bank

 

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Chapter 5: The Erythrocyte

Multiple-Choice Questions

Level I

1. Choose the correct order of normoblastic maturation from least mature to most mature.
   1. Erythrocyte, reticulocyte, polychromatophilic normoblast, orthochromatic normoblast, basophilic normoblast, pronormoblast
   2. Pronormoblast, basophilic normoblast, polychromatophilic normoblast, orthochromatic normoblast, reticulocyte, erythrocyte
   3. Basophilic normoblast, pronormoblast, polychromatophilic normoblast, orthochromatic normoblast, erythrocyte
   4. Pronormoblast, polychromatophilic normoblast, orthochromatic normoblast, reticulocyte, erythrocyte

Correct Answer: B

(Objective 1)

1. Which of the following best correlates with an increased reticulocyte count?
   1. An increased bilirubin
   2. The presence of schistocytes in the peripheral blood smear
   3. Increased polychromasia on the peripheral blood smear
   4. Anisocytosis and poikilocytosis

Correct Answer: C

(Objective 2)

1. A reticulocyte count is 6%. This result is:
   1. Normal.
   2. Increased.
   3. Decreased.
   4. Erroneous.

Correct Answer: B

(Objective 3)

1. What is the primary mechanism by which erythropoietin affects RBC production?
   1. It expedites the maturation time of RBCs.
   2. It prevents premature apoptosis of RBCs.
   3. It stimulates facilitated incorporation of hemoglobin into RBCs.
   4. It stimulates expulsion of nuclei from nucleated erythrocyte precursors at a quicker rate.

Correct Answer: B

(Objective 4)

1. The deformability of the RBC membrane is attributed to which of the following?
   1. Peripheral proteins
   2. Integral proteins
   3. Sodium potassium pump
   4. Glycophorins

Correct Answer: A

(Objective 5)

1. Energy metabolism of the erythrocyte is achieved primarily through which of the following?
   1. Aerobic glycolysis
   2. Anaerobic glycolysis
   3. Asexual replication
   4. Mitosis

Correct Answer: B

(Objective 6)

1. Where does normal extravascular hemolysis take place?
   1. Blood vessels and bone marrow
   2. Lymph nodes and spleen
   3. Spleen and liver
   4. Bone marrow and liver

Correct Answer: C

(Objective 7)

1. The heme moiety produced during intravascular hemolysis is excreted by the body as:
   1. Biliverdin
   2. Urobilinogen
   3. Ferrochelatase
   4. Iron

Correct Answer: B

(Objective 7)

1. The life span of a normal erythrocyte is about:
   1. 9–11 days
   2. 5–7 days
   3. 120 days
   4. 6 hours

Correct Answer: C

(Objective 8)

1. Increased hemoglobin affinity for oxygen correlates to which of the following?
   1. An elevated 2,3-BPG
   2. A normal 2,3-BPG
   3. A decreased 2,3-BPG
   4. This cannot be determined.

Correct Answer: C

(Objective 9)

1. Red blood cell production begins with what cell?

1. Progenitor
2. Hematopoietic stem cell
3. CFU
4. BFU

Correct Answer:  B

(Objective 1)

1. Polychromatophilic red blood cells are commonly called what cell type?

1. Normoblast
2. Prorubricyte
3. Reticulocyte
4. Metarubricyte

Correct Answer:  C

(Objective 1, 2)

1. In a nonanemic adult, what is the normal range for peripheral blood reticulocytes?

1. 5–1.0%
2. 1–1.0%
3. 0–4.0%
4. 5–2.0%

Correct Answer:  D

(Objective 3)

1. Which part of the RBC membrane is essential for transporting proteins and anions across the membrane?

1. Lipids
2. Integral proteins
3. Peripheral proteins
4. Skeletal proteins

Correct Answer:  B

(Objective 5)

1. The average RBC is what size?

1. 20–25 mcM
2. 2–3 ,mcM
3. 12–15 mcM
4. 7–8 mcM

Correct Answer:  D

(Objective 8)

16. A blood sample has an elevated bilirubin, low haptoglobin, and low hemopexin. What is the most likely reason for this?
17. Increased extravascular hemolysis
18. Hypersplenism
19. Ineffective erythropoiesis
20. Increased intravascular hemolysis

Correct Answer: D

(Objective 7)

17. What analyte can help to differentiate between intravascular and extravascular hemolysis?
18. Hemoglobin
19. Bilirubin
20. Haptoglobin
21. Reticulocytes

Correct Answer: C

(Objective 7)

 

Level II

1. Of the following, who would have the highest concentration of erythropoietin?

1. A child
2. A patient who has just donated a kidney
3. An anemic patient
4. A pregnant mother

Correct Answer: C

(Objective 1)

1. All of the following proteins interact with spectrin in the RBC membrane except:

1. Glycophorin A
2. Ankyrin
3. Protein 4.1
4. Actin

Correct Answer: A

(Objective 2)

1. The abnormal increased influx of sodium and water in stomatocytes results from a defect in:

1. Peripheral proteins
2. Integral proteins
3. Actin
4. Spectrin

Correct Answer: B

(Objective 3)

1. What effect would a deficiency in G6PD have on RBC survival?

1. It would increase the survival of the RBCs.
2. It would decrease the survival of the RBCs.
3. It would have no effect on the survival of the RBCs.
4. This cannot be determined.

Correct Answer: B

(Objective 4)

1. Which of the following “marks” the RBC as senescent?

1. A cluster of band 3 proteins on the RBC membrane
2. An RBC with denatured hemoglobin on the RBC membrane
3. An elongated RBC
4. Hyperphosphorylation of integral proteins

Correct Answer: A

(Objective 5)

1. The production of 2,3-BPG occurs in which erythrocytic metabolic pathway?

1. Embden-Meyerhof pathway
2. Hexose monophosphate shunt

c   Rapoport-Luebering shunt

1. All of the above

Correct Answer: C

(Objective 4)

1. Which metabolic pathway protects hemoglobin from oxidation via NADH?

1. Rapoport-Luebering shunt
2. Embden Meyerhof pathway
3. Hexose monophosphate shunt
4. Methemoglobin reductase pathway

Correct Answer: D

(Objective 4)

1. Predict the results of erythropoietin in a patient with hypoxia.

1. It will be increased.
2. It will be normal.
3. It will be decreased.
4. This cannot be determined.

Correct Answer: A

(Objective 6)

1. What growth factor influences the production of the erythrocyte?

1. Transforming growth factor-β
2. Interferon-γ
3. Erythropoietin
4. CFU-E

Correct Answer:  C

(Objective 1)

1. Which major integral protein is used in the mechanism to transport the chloride–bicarbonate exchange?

1. Glucose transporter
2. Anion exchange protein
3. Ankyrin
4. Adducing

Correct Answer:  B

(Objective 3)

1. What protein is the major membrane attachment point of the latticework that laminates the inner lining of the RBC membrane?

1. Tropomodulin
2. Troponyosin
3. Ankyrin
4. Band 3

Correct Answer:  D

(Objective 2)

1. What element or property contributes to the normal shape of the RBC?

1. Sodium
2. Spectrin tetramer
3. Calcium
4. Magnesium

Correct Answer:  B

(Objective 2)

1. What contributes to the RBC cell’s membrane integrity?

1. Skeletal proteins
2. Glycolytic pathway
3. 2,3-BPG
4. Methemoglobin reductase

Correct Answer:  A

(Objective 2)

14. Which pathway produces the energy required for proper RBC function from ~90% of the consumed glucose:

1. 1. Methemoglobin reductase
   2. Hexose monophosphate shunt
   3. Glycolytic
   4. Rapoport-Leubering shunt

Correct Answer:  C

(Objective 4)

15. Which of the following molecules is a senescence signal when it is exposed on the outer leaflet of the erythrocyte?
    1. Band 3
    2. Ankyrin
    3. Phosphatidylethanolamine (PE)
    4. Phosphatidylserine (PS)

Correct Answer:  D

(Objective 5)

 

 

Short-Answer Questions

1. Explain how the body catabolizes hemoglobin in both extravascular and intravascular hemolysis.

Answer:  Extravascular: Hemoglobin dissociates into heme + globin; globin goes amino acid pool where it is reutilized; heme → biliverdin → bilirubin bilirubin + albumin → bilirubin diglucuronide → urobilinogen → stool and urine excretion.

 

Intravascular: Hemoglobin is released directly into the blood where it complexes with haptoglobin and is carried to the liver where it is catabolized the same way as in extravascular hemolysis. If haptoglobin is depleted, the hemoglobin dimers can be filtered by the kidney; also with haptoglobin depletion some hemoglobin is oxidized to methemoglobin; the heme binds to hemopexin and albumin, and both travel to the liver and follow same mechanism for excretion as extravascular.

 (Objectives 7, Level I)

1. Explain the effect of the following on RBC survival.
   1. An absence of G6PD
   2. An absence of PK
   3. A defect in spectrin
   4. A defect in ankyrin

Answer:  (a) An absence of G6PD: RBC has a shortened life span resulting from impaired reduction of cellular oxidants via the hexose monophosphate (HMP) shunt. RBC is prone to oxidative damage that causes premature lysis.

(b) An absence of PK: RBC has a shortened life span resulting from impaired glycolysis and production of ATP via the Embden-Meyerhof (glycolytic) pathway.

(c)A defect in spectrin: Spectrin is a peripheral protein involved in  RBC deformability. Defects in the spectrin molecule produce a rigid RBC that is not deformable and has a shortened life span because of an increased surface–volume ratio.

(d)A defect in ankyrin: Ankyrin is a peripheral protein responsible for RBC deformability. Defects in the ankyrin molecule produce a rigid RBC that is not deformable and has a shortened life span because of  an increased surface–volume ratio.

(Objectives 3, 4, Level II)

1. Explain how EPO regulates RBC production.

Answer:  Erythropoiesis is governed by a negative feedback mechanism centered on hypoxic conditions. Hypoxia stimulates synthesis of EPO by the kidney.  When erythropoiesis is sufficient to correct the hypoxia, the negative feedback is shut off. This is done by downregulating kidney synthesis of EPO.

 (Objective 1, Level II)

 

4. Match the following characteristics with the appropriate stage of maturing erythrocytes:
5. Erythrocyte
6. Pronormoblast
7. Polychromatophilic normoblast
8. Reticulocyte
9. Basophilic normoblast
10. Orthochromic normoblast

 

_____  Earliest morphologically recognizable erythrocytic cell

_____  First visible appearance of hemoglobin

_____  Stage when the nucleus becomes pyknotic and is extruded

_____  First stage without a nucleus

_____  First stage without ribosomes

_____  Last stage capable of mitosis

 

Answer:  b, e, f, d, a, c

(Objective 1, Level 1)

5. Describe the nuclear and cytoplasmic morphologic changes in erythrocytes during maturation.

Answer:  As erythrocytes mature, the N:C ratios decrease progressively, the nucleus undergoes progressive chromatin clumping, the nucleus undergoes progressive decrease in size and is eventually extruded, and the cytoplasm begins as basophilic and progressively becomes acidophilic.

(Objective 1, Level 1)