MLT 236 Final Exam

Why is it important that synthesis of globin chains and heme be balanced in the RBCs?

An excess of one of the components of hemoglobin decreases RBC survival.

The globin chains making up Hb A are

two a and two b chains.

Which of the following is true regarding carboxyhemoglobin?

Smokers have increased levels.

Why is heme located inside a globin chain pocket surrounded by hydrophobic amino acids?

protects iron from being oxidized to its ferric form

Which of the following is true for the relative affinity of hemoglobin for oxygen in the lungs and tissue with the oxygen dissociation curve in its normal position? Lungs Tissue

high low

Where is heme produced?

Red blood cell precursors in the bone marrow

The A1c-modified component of Hb A is increased in what condition?

uncontrolled diabetes mellitus

Select the form of hemoglobin that contains iron in the ferric rather than the ferrous state.

methemoglobin

Why does Hb F have a higher oxygen affinity than adult hemoglobin?

It is necessary to extract oxygen from the maternal blood supply.

Which of the following causes a shift to the right on the oxygen dissociation curve?

severe anemia

Soluble transferrin receptor (sTfR) levels increase when intracellular iron levels are

decreased.

Good dietary sources of iron include all except

fruit.

What is the plasma carrier protein for iron?

apotransferrin

A patient has a serum iron of 10 g/dL and a total iron-binding capacity (TIBC) of 490 g/dL. What is the percent saturation of transferrin?

2%

Heme is composed of iron and

protoporphyrin IX.

Acute (24-hour) assessment of the amount of iron that is available for hemoglobin production is best identified by measuring the

amount of hemoglobin in reticulocytes.

The serum iron and TIBC results given in Question 7 are consistent with:

iron deficiency.

Where is the largest percentage of iron in the body located?

attached to hemoglobin in erythrocytes

The serum ferritin is used more often than bone marrow or liver biopsies to assess iron stores because it is

less invasive.

Select the condition where an acute increase in ferritin levels can be detected without a specific increase in the amount of systemic body iron?

bacterial infection

Normal adult Hb A contains which polypeptide chains?

alpha and beta

Iron is transported in plasma via

transferrin

Normal Hemoglobin Reference Range for an adult male is: ___________ g/dL

13.5-18.0 g/dL

Normal adult female hemoglobin reference range is: ___________ g/dL

12.0-15.0

When hematopoiesis occurs in the liver in an adult, it is called:

extramedullary

Apoptosis is

programmed cell death

Which of the following is a morphologically identifiable precursor cell using Wright stain?

promyelocyte

Where are developing red cells located in the bone marrow?

adjacent to the outer surfaces of the vascular sinuses

How many blood cells are made each day in the bone marrow of a normal adult?

hundreds of billions

Kupffer cells, found in the liver, are

macrophages

Enlarged lymph nodes are commonly found in all of the following except

liver cirrhosis.

Colony-stimulating factors

are produced by many cells.

The thymus is responsible for the initial development of

T cells.

All of the following functions are performed by cytokines except

inducing macrophages to attack senescent cells.

What stimulates production of erythropoietin?

decreased oxygen level in tissue

When compared with mature erythrocytes, reticulocytes

are larger and bluer on Wright stain from remnant ribonucleic acid (RNA).

Depletion of serum haptoglobin indicates

intravascular hemolysis

Which of the following is true of red cell precursors as they mature?

The cytoplasm becomes less basophilic.

The breakdown products of heme go through several biochemical degradations to form

bilirubin.

What is the main site for iron storage in the bone marrow?

macrophages

What mechanism is responsible for the destruction of the majority of normal senescent erythrocytes?

phagocytosis by splenic macrophages

Where is erythropoietin synthesized?

kidney

Which of the following correctly describes a normal mature erythrocyte?

a 7- to 8-mm biconcave disc that lives 120 days

Which of the following provides a negative feedback for heme synthesis, thus helping to control, by decreasing, its synthesis?

concentration of heme in the developing RBC

What is the effect of an increased concentration of 2,3-BPG in the RBC?

shifts the oxygen dissociation curve to the right

An increase in the concentration of 2,3-BPG

is present in patients with severe anemia and decreased blood pH (acidosis).

Which of the following statements is true about Hb F?

It is the major hemoglobin during fetal life.

How many molecules of oxygen can one molecule of hemoglobin carry?

four

Which of the following is true for apotransferrin?

It can bind two molecules of ferric iron.

Which two organs are the major storage sites for iron in a normal individual?

liver and spleen

What is responsible for erythrocyte deformability and maintaining cell shape?

membrane proteins

Which of the following is the metabolic pathway that generates a net gain of two molecules of ATP for erythrocyte energy needs?

EMP

What is the normal life span of a red cell in circulation?

120 days

Which of the following is the metabolic pathway that regulates oxygen delivery to tissues?

2,3-BPG

What components of the erythrocyte membrane are responsible for its negative charge and are also blood group antigens?

transmembrane proteins

The principle energy source for mature red blood cells (RBCs) is

ATP generated from anaerobic glycolysis.

Which of the following is most responsible for the strength and pliancy of the red cell membrane?

spectrin

Glucose-6-phosphate dehydrogenase (G6PD) is

necessary to maintain reduced glutathione in the mature red cell.

What important function does 2,3-BPG perform?

facilitates the delivery of oxygen to tissue

Why is the mature erythrocyte unable to synthesize proteins or lipids?

It has no nucleus.

Normal Newborn Hematocirt is

48 - 68 %

Normal Red Blood Cell Distribution (degree of variation of RBC volume) RDW is

11.5 - 14.5 %

Why is too much iron dangerous?

Free radicals and superoxide from from ferrous iron plus oxygen damage cell membranes

Where is most of the iron in the body found?

attached to Hg in the RBCs

What percentage of red cells is destroyed and replaced daily in a normal adult?

1%

Lack of accessible iron is the mechanism for iron deficiency in which of the following?

anemia of chronic inflammation (ACI)

Which of the following is elevated in megaloblastic anemia?

mean cell hemoglobin (MCH)

What is the treatment of choice for long-term survival for patients younger than 40 years old with aplastic anemia?

hematopoietic stem cell transplant

Which of the following disorders would be consistent with the previously mentioned parameters?

vitamin B12 deficiency

What surface antigen on cells identifies them as a hematopoietic stem cell?

CD34

What salivary protein is important for the transport of dietary vitamin B12 to the small intestine?

haptocorrin

Which of the following is most useful for considering the diagnosis of bone marrow failure?

an absolute neutrophil count of less than 0.5 ´ 103/dL

Which of the following would be an unusual bone marrow finding in aplastic anemia?

increased megakaryocytes

Which of the following red blood cell (RBC) findings is specific for a certain condition as opposed to being nonspecific and found in many conditions?

sickle cells

Which of the following would point to iron deficiency anemia as opposed to the ACI?

high transferrin

Which of the following tests for PA would be easiest for the patient?

vitamin B12 assay

Patients with vitamin B12 or folate deficiency commonly experience symptoms related to

gastrointestinal and neurologic systems.

Paroxysmal nocturnal hemoglobinuria has a high degree of association with which one of the following disorders?

aplastic anemia

Basophilic stippling

Precipitated RNA

Pappenheimer body

ferric non heme iron

Heinz body

denatured hemoglobin

Howell-Jolly body

DNA

Which of the following is true of ineffective erythropoiesis?

RBC production in bone marrow is increased.

How does lead exposure and the porphyrias cause anemia?

interfere with heme production

All of the following are true about hepcidin except that

it decreases in response to increased ferritin.

Two different patients both have hemoglobins in the 5.0 to 6.0 g/dL range. One has pallor, fatigue, and headaches, whereas the other is experiencing life-threatening shock. Which of the following is probably the major difference between the two patients?

how quickly the anemia developed

Why is lead poisoning of particular concern in children?

Impaired mental development may occur.

Pancytopenia is a term that means

decrease in red cells, white cells, and platelets.

Which of the following is an example of a morphologic classification of anemia?

normocytic normochromic

All of the following are physiologic adaptations the body makes when a slow drop in the number of red cells occurs except

oxygen dissociation curve shifts to left.

Diepoxybutane causes chromosomal breakage in which of the following disorders?

Fanconi anemia

A patient has a decreased vitamin B12 assay. The Schilling test detects labeled vitamin B12 in the urine when it is given with IF. What is the correct interpretation?

PA

Most of the clinical findings in the porphyrias are related to

accumulated porphyrin compounds in tissue.

Compare results of various tests in effective versus ineffective erythropoiesis.

Both have increased rate of erythropoiesis in the bone marrow.

Methotrexate and some other chemotherapeutic drugs work by

competing with folate.

Megaloblastic anemias are caused by a defect in the synthesis of

deoxyribonucleic acid (DNA).

Which of the following is an inherited disorder with pancytopenia, malformed kidneys, and mental deficiency?

Fanconi anemia

What is the most effective treatment for PA?

injections of vitamin B12

What is the best definition of anemia?

decreased hemoglobin, hematocrit, and red cell count compared with healthy people in the same demographic group

Which of the following results is or are typical in stage 3 iron deficiency anemia?

low mean cell volume (MCV), MCH, and mean cell hemoglobin concentration (MCHC)