Hematology MCQs with Answer and Explanations | Chapter 10

Answer: It is an acquired hemolytic anemia

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired disorder resulting from a somatic mutation in hematopoietic stem cells, leading to complement-mediated hemolysis.

The other options are incorrect:

• It is inherited as a sex-linked trait: PNH is not inherited in a sex-linked manner.
• It is inherited as an autosomal dominant trait: PNH is not inherited as an autosomal dominant trait; it is acquired.
• It is inherited as an autosomal recessive trait: PNH is not inherited as an autosomal recessive trait; it is an acquired condition.

Answer: Reticulocytopenia

Reticulocytes are young, immature red blood cells. In HUS, the body is typically trying to compensate for the destroyed red blood cells by producing more red blood cells, leading to an increase in reticulocytes.

The other options are incorrect:

• Hemorrhage: Uncontrolled bleeding can occur due to low platelets in HUS.
• Thrombocytopenia: A hallmark feature of HUS is a low platelet count.
• Hemoglobinuria: Breakdown of red blood cells releases hemoglobin, which can appear in the urine in HUS.

Answer: Paroxysmal nocturnal hemoglobinuria

The autohemolysis test, which measures the spontaneous breakdown of red blood cells, is not typically positive in paroxysmal nocturnal hemoglobinuria (PNH).

The other options are incorrect:

• Glucose-6-phosphate dehydrogenase (G6PD) deficiency: The autohemolysis test is positive due to increased red cell fragility under oxidative stress.
• Hereditary spherocytosis: Positive autohemolysis test due to intrinsic defects in the red cell membrane.
• Pyruvate kinase deficiency: Positive autohemolysis test due to a lack of ATP production leading to red cell membrane instability.

Answer: Increased haptoglobin

Haptoglobin is a protein in the blood that binds to free hemoglobin released from broken down red blood cells. In hemolytic anemia, where red blood cells are destroyed excessively, haptoglobin levels typically decrease as it gets used up to bind to the free hemoglobin.

The other options are incorrect:

• Methemoglobinemia: This condition involves an abnormal form of hemoglobin that can’t carry oxygen effectively. It can sometimes occur due to hemolytic anemia.
• Hemoglobinuria: Presence of hemoglobin in the urine, a sign of red blood cell breakdown seen in hemolytic anemia.
• Hemoglobinemia: High levels of hemoglobin in the blood, which can occur when red blood cells are being destroyed faster than they are being produced (hemolytic anemia).

Answer: Spherocytic red cells

Autoimmune hemolytic anemia is characterized by the presence of spherocytes, which are spherical red blood cells that result from the immune system targeting and damaging red blood cells.

The other options are incorrect:

• Increased levels of plasma C3: While complement component C3 can be involved in autoimmune processes, increased levels are not a defining feature of autoimmune hemolytic anemia.
• Decreased osmotic fragility: Autoimmune hemolytic anemia usually shows increased osmotic fragility due to the presence of spherocytes, which are more prone to lysis in hypotonic solutions.
• Decreased unconjugated bilirubin: In autoimmune hemolytic anemia, there is typically an increase in unconjugated bilirubin due to the breakdown of red blood cells, not a decrease.

Answer: G6PD deficiency

“Bite cells” are red blood cells with a portion removed, typically seen in G6PD deficiency due to the removal of Heinz bodies by the spleen.

The other options are incorrect:

• Rh null trait: This is a rare blood type where a person lacks all Rh antigens. It doesn’t typically cause bite cells.
• Chronic granulomatous disease (CGD): This is an immune system disorder that affects white blood cells, not red blood cells. Bite cells are not a typical feature of CGD.
• PK deficiency (Pyruvate kinase deficiency): Similar to G6PD deficiency, PK deficiency is another enzyme deficiency in red blood cells. However, bite cells are less commonly seen in PK deficiency compared to G6PD deficiency.

Answer: RBC indicies

The morphological classification of anemias is based on RBC indices, which include measurements like mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC). These indices help determine the size and hemoglobin content of red blood cells.

The other options are incorrect:

• M:E ratio: The myeloid to erythroid ratio is used to assess bone marrow activity but does not classify anemias morphologically.
• Prussian blue stain: This stain is used to detect iron in tissues, particularly for diagnosing conditions like sideroblastic anemia, but it is not used for the morphological classification of anemias.
• Reticulocyte count: The reticulocyte count measures the number of young red blood cells in the blood, indicating bone marrow activity, but it does not classify anemias based on morphology.

Answer: Peripheral blood pancytopenia

Aplastic anemia is characterized by peripheral blood pancytopenia, which refers to low counts of red blood cells, white blood cells, and platelets in the bloodstream due to bone marrow failure.

The other options are incorrect:

• A monoclonal disorder: Aplastic anemia is not typically a monoclonal disorder; it involves failure of the bone marrow to produce an adequate number of blood cells.
• Tumor infiltration: Aplastic anemia is not caused by tumor infiltration; rather, it results from autoimmune destruction of hematopoietic stem cells or exposure to certain drugs or toxins.
• Defective DNA synthesis: While defective DNA synthesis can occur in some types of anemias, it is not a characteristic feature of aplastic anemia.

Answer: Bizarre multinucleated erythroblasts

Congenital dyserythropoietic anemias (CDAs) are characterized by the presence of bizarre multinucleated erythroblasts in the bone marrow, which are abnormal erythroid precursor cells with multiple nuclei.

The other options are incorrect:

• Cytogenetic disorders: While some genetic mutations underlie CDAs, they are not typically considered cytogenetic disorders in the same sense as conditions like Down syndrome or Turner syndrome.
• Megaloblastic erythropoiesis: Megaloblastic erythropoiesis is a feature of megaloblastic anemias, not congenital dyserythropoietic anemias.
• An elevated M:E ratio: An elevated myeloid to erythroid (M:E) ratio is more characteristic of myeloproliferative disorders or certain types of leukemia, not CDAs, which are primarily characterized by dyserythropoiesis.

Answer: Schistocytes and nucleated RBCs

Microangiopathic hemolytic anemia (MAHA) is characterized by the presence of schistocytes (fragmented red blood cells) and nucleated red blood cells (nRBCs) in the peripheral blood smear, which indicate red cell destruction and bone marrow response to the hemolytic process.

The other options are incorrect:

• Target cells and cabot rings: Target cells and cabot rings are associated with conditions like thalassemia and lead poisoning, not microangiopathic hemolytic anemia.
• Toxic granulation and Dohle bodies: Toxic granulation and Dohle bodies are morphological features observed in neutrophils and are indicative of severe infections or toxic conditions, not specific to microangiopathic hemolytic anemia.
• Pappenheimer bodies and basophilic stippling: Pappenheimer bodies are iron-containing granules seen in sideroblastic anemia, while basophilic stippling is associated with lead poisoning or thalassemia, but not typically with microangiopathic hemolytic anemia.

Answer: Chloramphenicol

Chloramphenicol is most often implicated in the development of aplastic anemia. It is known to suppress bone marrow function, leading to a decrease in the production of blood cells.

The other options are incorrect:

• Sulfonamides: While sulfonamides can also cause hematological adverse effects, including agranulocytosis and hemolytic anemia, they are not as commonly associated with aplastic anemia as chloramphenicol.
• Penicillin: Penicillin antibiotics are not typically associated with aplastic anemia. However, they can cause other adverse reactions, such as allergic reactions and drug-induced hemolytic anemia.
• Tetracycline: Tetracycline antibiotics are not commonly implicated in the development of aplastic anemia. They are more often associated with side effects like gastrointestinal upset and photosensitivity.

Answer: Hereditary, intracorpuscular RBC defect

Sickle cell disorders are hereditary conditions characterized by an intracorpuscular defect, meaning the defect originates within the red blood cells (RBCs) themselves. These disorders are caused by mutations in the HBB gene, leading to the production of abnormal hemoglobin (HbS) that causes the characteristic sickle-shaped RBCs.

The other options are incorrect:

• Hereditary, extracorpuscular RBC defect: There is no such classification as an extracorpuscular RBC defect in the context of sickle cell disorders. The defect originates within the RBCs, not outside of them.
• Acquired, intracorpuscular RBC defects: Sickle cell disorders are hereditary conditions and not acquired. They result from genetic mutations passed down from parents to offspring.
• Acquired, extracorpuscular RBC defects: Sickle cell disorders are not acquired conditions, meaning they are not developed later in life due to external factors. They are present from birth due to genetic inheritance

Answer: Autoimmune hemolytic anemia

Autoimmune hemolytic anemia (AIHA) occurs when the immune system mistakenly attacks healthy red blood cells. This attack can damage the red blood cell membrane, sometimes causing them to become sphere-shaped (spherocytes).

The other options are incorrect:

• Pelger-Huet anomaly: This is a harmless inherited condition affecting the appearance of white blood cells, not red blood cells. It doesn’t cause spherocytes.
• Pernicious anemia: This is a vitamin B12 deficiency anemia. While it can affect red blood cell size and shape, it doesn’t typically cause spherocytosis. The red blood cells in pernicious anemia are more likely to be macrocytic (larger than normal).
• Sideroblastic anemia: This is a group of anemias characterized by iron overload within red blood cell precursors. While the red blood cells may appear abnormal, spherocytosis is not a typical finding.

Answer: Increased MCV

Increased Mean Corpuscular Volume (MCV) indicates larger-than-normal red blood cells, which can be seen in conditions like megaloblastic anemia or certain liver diseases.

The other options are incorrect:

• Reduced platelets: Platelet count is not typically affected by changes in red blood cell parameters.
• Increased MCHC: Increased Mean Corpuscular Hemoglobin Concentration (MCHC) is associated with conditions like spherocytosis, not the described scenario.
• Decreased red cell distribution width (RDW): RDW measures the variation in red blood cell size and is usually increased in cases of anemia due to various causes, so it wouldn’t be decreased.

Answer: Howell-Jolly bodies

The spleen normally removes Howell-Jolly bodies, remnants of the red blood cell nucleus. After splenectomy, these bodies may be seen in peripheral blood smears.

The other options are incorrect:

• Toxic granulation: These are caused by lead poisoning or other heavy metal intoxication, not splenectomy.
• Malarial parasite: This indicates a malaria infection, not a post-splenectomy finding.
• Siderotic granules: These are iron-laden granules seen in some anemias, but not specifically related to splenectomy.

Answer: Red cell regeneration

Reticulocytosis refers to an increased number of reticulocytes in the blood, which indicates bone marrow response to increased demand for red blood cell production, commonly seen in conditions like anemia or blood loss.

The other options are incorrect:

• Response to inflammation: Reticulocytosis is not typically associated with inflammation.
• Neoplastic process: Neoplastic processes are related to abnormal cell growth, not the increase in reticulocytes.
• Aplastic anemia: Aplastic anemia is characterized by bone marrow failure and decreased production of all blood cell types, including reticulocytes.

Answer: Misshappen budding fragmented cells

Hereditary pyropoikilocytosis (HP) is characterized by the presence of misshapen, budding, and fragmented red blood cells due to a defect in the red cell membrane.

The other options are incorrect:

• Increased pencil-shaped cells (elliptocytes): While elliptocytosis can be a feature of some red blood cell membrane disorders, HPP is characterized by more extreme poikilocytosis, not just elliptocytes.
• Increased oval macrocytes: Macrocytes are simply large red blood cells, and ovalocytosis refers to a specific oval shape. HPP doesn’t have a specific size or shape, but rather extreme variation.
• Bite cells (stomatocytes): Stomatocytes have a central, mouth-like indentation. While they can be seen in some anemias, they are not the defining feature of HPP.

Answer:

This procedure involves measuring the absorbance of amniotic fluid at a specific wavelength (450 nm) to detect increased bilirubin levels, which can indicate hemolytic disease of the newborn.

The other options are incorrect:

• Creatinine: Creatinine is a waste product filtered by the kidneys and doesn’t directly indicate HDN.
• Lecithin/sphingomyelin ratio (L/S ratio): This ratio is used to assess fetal lung maturity, not HDN.
• Estriol: Estriol is an estrogen produced by the placenta. While abnormal estriol levels can indicate some pregnancy complications, it’s not a specific test for HDN.

Answer: Hemolytic

Severe burns can lead to hemolysis due to factors like mechanical trauma, oxidative stress, and complement activation, resulting in the destruction of red blood cells and subsequent hemolytic anemia.

The other options are incorrect:

• Macrocytic: Macrocytic anemia is characterized by larger-than-normal red blood cells and is not typically associated with severe burns.
• Microcytic: Microcytic anemia is characterized by smaller-than-normal red blood cells and is not typically associated with severe burns.
• Aplastic: Aplastic anemia is caused by bone marrow failure, leading to decreased production of all blood cell types, not specifically related to burns.

Answer: Size of the particle being counted

Automated blood cell counters often use electrical impedance or light scattering to differentiate and count blood cells. These methods rely on the size of the particle being measured, as red blood cells, white blood cells, and platelets have distinct sizes.

The other options are incorrect:

• Amount of hemoglobin in the red cell: While there are instruments that measure hemoglobin content, this isn’t the primary function of cell counters that provide complete blood count (CBC) results with cell differentials.
• Weight of the hemoglobin in the red cell: Hemoglobin weight is not directly used in automated blood cell counting.
• Value of the cell indices: Cell indices, like MCV (mean corpuscular volume), are calculated based on measurements made by the counter, including size. The counter itself doesn’t directly assess these indices.

Answer: RBC and WBC

A high background count in an automated blood cell counter can interfere with the accurate counting of both red blood cells (RBC) and white blood cells (WBC).

The other options are incorrect:

• Hct and WBC: High background count typically affects cell counting, not hematocrit (Hct) measurement.
• RBC and Hgb: High background count can interfere with accurate RBC counting but does not directly affect hemoglobin (Hgb) measurement.
• WBC and Hgb: While a high background count can interfere with WBC counting, it does not typically affect hemoglobin (Hgb) measurement.

Answer: A heavy buffy coat

A heavy buffy coat, indicating an increased number of white blood cells, may suggest leukemia during a manual hematocrit determination.

The other options are incorrect:

• Hemolysis: Hemolysis refers to the breakdown of red blood cells and is not typically indicative of leukemia during a hematocrit determination.
• Icteric plasma: Icteric plasma, indicating jaundice, is not specifically associated with leukemia during a hematocrit determination.
• A high hematocrit: A high hematocrit may be seen in conditions like polycythemia vera but is not specific to leukemia during a manual hematocrit determination.

Answer: Nasal secrection for eosinophiles

Hansel’s stain is a simple and rapid method specifically designed to detect eosinophils in body fluids like urine or nasal secretions. It’s particularly useful for identifying eosinophils in nasal smears for allergy diagnosis.

The other options are incorrect:

• Phagocytic neutrophils: While Hansel’s stain can technically stain some white blood cells, it’s not specific for neutrophils and wouldn’t be the preferred method for identifying them. Standard blood smears with Wright-Giemsa stain are better suited for examining neutrophils.
• Leukocytes in spinal fluid: Spinal fluid analysis typically uses cell counts and other stains to differentiate white blood cells, not Hansel’s stain specifically.
• Circulating eosinophils: While Hansel’s stain can be used on blood smears in some cases to identify eosinophils, peripheral blood smears with Wright-Giemsa stain are more commonly used for this purpose.

Answer: The cell decreases in size

As most blood cells mature, they undergo a process of differentiation where they become specialized for their function. This often involves a reduction in cytoplasmic organelles and a condensation of the nucleus, leading to a decrease in overall cell size.

The other options are incorrect:

• There is no change in the cell’s size: Maturation typically involves changes in size for most blood cell types.
• The nucleus increases in size: In most cases, the nucleus condenses or even gets expelled during maturation.
• The cell increases in size: While some exceptions exist, generally, blood cells don’t significantly increase in size as they mature.

Answer: Markedly pale in central color

Hypochromia means “pale color.” An RBC with hypochromia has a decreased amount of hemoglobin, resulting in a paler appearance, particularly in the central region of the cell when viewed under a microscope.

The other options are incorrect:

• Packed with hemoglobin: This describes a normochromic RBC, which has a normal amount of hemoglobin and appears well-colored.
• Variable in shape: Hypochromia is related to hemoglobin content, not necessarily shape. While some anemias with hypochromia may also have abnormal shapes, shape isn’t the defining feature.
• Markedly bluish in color: This wouldn’t be typical for hypochromia. Red blood cells usually appear pink or red under a microscope.

Answer: Do not count nucleated red blood cells

Most automated cell counters exclude nucleated red blood cells from their counts.

The other options are incorrect:

1. Count nucleated red blood cells with leukocytes: Automated counters typically differentiate between leukocytes and nucleated red blood cells.
2. Count nucleated red blood cells with platelets: Platelets and nucleated red blood cells are usually distinguished in automated cell counts.
3. Count nucleated red blood cells with erythrocytes: Nucleated red blood cells are typically excluded from erythrocyte counts in automated cell counts.

Answer: 0.50% NaCl

The osmotic fragility test is normal when hemolysis begins in a solution with a lower concentration of salt, such as 0.50% NaCl.

The other options are incorrect:

• 0.90% NaCl: This concentration of NaCl would likely result in hemolysis before the test is considered normal.
• 1.34% NaCl: This concentration is too high for normal osmotic fragility testing; hemolysis would likely occur at a lower concentration.
• 0.85% NaCl: While closer to the correct concentration, 0.85% NaCl may still be too high for a normal osmotic fragility test.

Answer: Alkaline picrate

Most methods for blood creatinine determination involve the reaction of creatinine with alkaline picrate to form a colored complex.

The other options are incorrect:

• Sulfuric acid: Sulfuric acid is not typically used in methods for blood creatinine determination.
• Ammonium hydroxide: Ammonium hydroxide is not commonly involved in the reaction for blood creatinine determination.
• Acetic anhydride: Acetic anhydride is not typically used in methods for blood creatinine determination.

Answer: Nasal secrection for eosinophiles

Hansel’s stain is a simple and rapid method specifically designed to detect eosinophils in body fluids like urine or nasal secretions. It’s particularly useful for identifying eosinophils in nasal smears for allergy diagnosis.

The other options are incorrect:

• Circulating eosinophils: While Hansel’s stain can be used on blood smears in some cases to identify eosinophils, peripheral blood smears with Wright-Giemsa stain are more commonly used for this purpose.
• Phagocytic neutrophils: While Hansel’s stain can technically stain some white blood cells, it’s not specific for neutrophils and wouldn’t be the preferred method for identifying them. Standard blood smears with Wright-Giemsa stain are better suited for examining neutrophils.
• Leukocytes in spinal fluid: Spinal fluid analysis typically uses cell counts and other stains to differentiate white blood cells, not Hansel’s stain specifically.

Answer: Reticulocytes

Brilliant cresyl blue or new methylene blue stains are used to stain and count reticulocytes in peripheral blood smears.

The other options are incorrect:

• Platelets: These stains are not used for counting platelets.
• Howell-Jolly bodies: These stains are not used for counting Howell-Jolly bodies.
• Malaria: These stains are not typically used for staining malaria parasites.

Answer: Heniz bodies

Supravital staining of red cells with a deficiency of G-6-PD will reveal the presence of Heinz bodies, which are denatured hemoglobin precipitates.

The other options are incorrect:

• Rubriblasts: Rubriblasts are immature red blood cell precursors and are not related to G-6-PD deficiency.
• Howell-Jolly bodies: Howell-Jolly bodies are nuclear remnants found in erythrocytes and are not specific to G-6-PD deficiency.
• Plasmodium species: Plasmodium species are malaria parasites and are not detected through supravital staining for G-6-PD deficiency.

Answer: 1:20

White blood cell counts require diluting the blood sample to ensure accurate counting under a microscope. A dilution of 1:20 is the standard ratio used in most white blood cell count procedures.

The other options are incorrect:

• 04:20: This dilution is too weak and would result in too few white blood cells for accurate counting.
• 01:10: This dilution is also too weak and wouldn’t be sufficient for optimal counting.
• 01:50: While closer, a 1:20 dilution is the standard used for most accurate results.

Answer: Size of the particle being counted

Some automated blood cell counters operate based on the size of the particles being counted, using methods like impedance or flow cytometry.

The other options are incorrect:

• Amount of hemoglobin in the red cell: While hemoglobin concentration is measured by some counters, it’s not the primary principle used for counting cells.
• Value of the cell indices: Cell indices are calculated parameters derived from red blood cell count, hemoglobin concentration, and red cell indices like mean corpuscular volume (MCV) and mean corpuscular hemoglobin concentration (MCHC); they are not the primary principle for cell counting in automated counters.
• Weight of the hemoglobin in the red cell: Hemoglobin weight is not directly used in automated blood cell counting.

Answer: Dolichos biflorus serum

The ABO blood typing system differentiates blood types based on the presence or absence of specific carbohydrates (sugars) on red blood cells. Dolichos biflorus lectin is a protein that specifically agglutinates (clumps) A2 red blood cells. This test helps distinguish between A1 and A2 subtypes within the A blood type.

The other options are incorrect:

• Anti-A serum: This is the standard reagent used to identify the presence of the A antigen on red blood cells. It wouldn’t differentiate between A1 and A2 subtypes.
• Anti-AB serum: This serum agglutinates both A and B type red blood cells and is used for initial ABO blood typing, not differentiating A subtypes.
• Anti-A2 serum: While theoretically possible, anti-A2 serum is not a common blood bank reagent because Dolichos biflorus lectin is a more specific and reliable method for A1/A2 differentiation.

Answer: Landsteiner

Landsteiner is credited with proposing the most readily acceptable theory of ABO inheritance, which laid the foundation for understanding blood group systems.

The other options are incorrect:

• Levine: Levine made significant contributions to blood banking and discovered the Rh factor but is not credited with the ABO inheritance theory.
• Bernstein: Bernstein contributed to immunology research but is not credited with the ABO inheritance theory.
• Weiner: Weiner made contributions to blood group systems but is not credited with the ABO inheritance theory.

Answer: Diluting fluid

Automated cell counters use a diluent, often a buffered saline solution, to dilute the blood sample for accurate counting. This diluent also helps to lyse (break open) red blood cells, allowing the counter to focus on counting white blood cells and platelets based on their size and other characteristics.

The other options are incorrect:

• Lysing reagent only: While some automated counters may use a lysing agent in a separate step to lyse red blood cells, the background count typically uses the diluent for initial dilution.
• Distilled water: Distilled water would lyse red blood cells but wouldn’t be ideal for other cell types and wouldn’t provide the optimal ionic environment for counting.
• Highly-diluted blood: Highly diluted blood would still contain red blood cells and wouldn’t provide a clean background for counting other cell types. The diluent offers a more controlled environment.

Answer: CD7+ Pro-T-Cells

CD7+ Pro-T-Cells are the earliest identifiable cells of T-cell lineage during maturation.

The other options are incorrect:

• CD5+ Pre-T-Cells: While CD5 is expressed on T cells, CD7 is expressed earlier in T-cell development.
• CD8+ Pro-T-Cells: CD8 is expressed on mature cytotoxic T cells, not on early T-cell progenitors.
• CD8+ Pre-T-Cells: CD8 is not typically expressed at the pre-T-cell stage of development; CD4 is more commonly associated with pre-T cells.

Answer: Type II

Rh incompatibility is classified as a Type II hypersensitivity reaction, involving the binding of antibodies to Rh antigens on red blood cells, leading to their destruction.

The other options are incorrect:

• Type I: Type I hypersensitivity reactions involve immediate IgE-mediated responses, such as allergies.
• Type III: Type III hypersensitivity reactions involve immune complex deposition and subsequent tissue damage.
• Type IV: Type IV hypersensitivity reactions are delayed cell-mediated responses, often seen in contact dermatitis or some autoimmune diseases.

Answer: Type II

Killer cells, such as cytotoxic T lymphocytes and natural killer cells, are associated with Type II hypersensitivity reactions, where they directly target and kill cells expressing specific antigens.

The other options are incorrect:

• Type I: Type I hypersensitivity reactions involve immediate IgE-mediated responses, such as allergies.
• Type III: Type III hypersensitivity reactions involve immune complex deposition and subsequent tissue damage.
• Type IV: Type IV hypersensitivity reactions are delayed cell-mediated responses, often seen in contact dermatitis or some autoimmune diseases.

Answer: Auto immune hemolytic anemia

Autoimmune hemolytic anemia is the prototype of Type II hypersensitivity reactions, where antibodies target and destroy red blood cells.

The other options are incorrect:

• Arthus reaction: The Arthus reaction is a Type III hypersensitivity reaction characterized by immune complex deposition in tissues.
• SLE (Systemic Lupus Erythematosus): SLE involves a variety of immune mechanisms and is not specifically a Type II hypersensitivity reaction.
• Contact dermatitis: Contact dermatitis is a Type IV hypersensitivity reaction mediated by T cells, not antibodies.

Answer: Hemopoiesis

Hemopoiesis is the biological process by which your body produces new blood cells. It occurs primarily in the red bone marrow, the spongy tissue found inside many of your bones.

The other options are incorrect:

• Mitosis: Mitosis is a cell division process for creating new cells that are genetically identical to the parent cell. While cell division is involved in hemopoiesis, it’s not the specific term for blood cell formation.
• Photosynthesis: Photosynthesis is the process by which plants convert sunlight, water, and carbon dioxide into glucose (sugar) for energy. It has nothing to do with blood cell production in animals.
• Complement fixation: Complement fixation is part of the immune system’s response to foreign invaders like bacteria or viruses. It doesn’t refer to blood cell formation.

Answer: True

Intravascular hemolysis specifically refers to the destruction of red blood cells (RBCs) within the circulatory system, meaning while they are traveling through your blood vessels. Trauma is one of the factors that can cause this rupturing of RBCs.

The other options are incorrect:

• False: If the statement were false, it would mean intravascular hemolysis doesn’t involve damage to RBCs within the bloodstream. This is incorrect because by definition, it occurs inside the circulatory system.

Answer: soccer-ball

In Chronic Lymphocytic Leukemia (CLL), lymphocytes often appear with hypercondensed nuclear chromatin, resembling a soccer-ball pattern.

The other options are incorrect:

• Basketball: This term is not used to describe the appearance of lymphocytes in CLL.
• Football: This term is not used to describe the appearance of lymphocytes in CLL.
• Tennis-ball: This term is not used to describe the appearance of lymphocytes in CLL.

Answer: True

Intravascular hemolysis occurs when red blood cells are destroyed within the blood vessels due to various traumatic factors, including mechanical damage, toxins, or immune reactions.

The other options are incorrect:

• False: This statement would incorrectly imply that intravascular hemolysis does not result from trauma to RBCs in circulation, which is not accurate.

Answer: 120

The average lifespan of a red blood cell (RBC) in humans is approximately 120 days. This means after about 120 days circulating in the bloodstream, the RBC is typically removed from circulation and broken down.

The other options are incorrect:

• 100 days: While close, 120 days is the generally accepted average lifespan.
• 200 days: This is too long. RBCs are constantly being produced and replaced, with a lifespan of around 120 days.
• 80 days: This is too short. The typical lifespan is closer to 120 days.

Answer: 3

Blood corpuscles, also known as blood cells, are of three main kinds: red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes).

The other options are incorrect:

• 5: There are not five main types of blood corpuscles.
• 4: While there are various subtypes of white blood cells, there are only three main categories of blood corpuscles.
• 2: This is too few. Red blood cells, white blood cells, and platelets are all essential components of blood.

Answer: Basophil

Basophils are a type of white blood cell that release heparin, an anticoagulant, and histamine, which is involved in inflammatory responses.

The other options are incorrect:

• Neutrophil: Neutrophils are the most abundant type of white blood cell and are the first responders to fight bacterial infections. They do not release heparin or histamine.
• Eosinophil: Eosinophils are involved in allergic reactions and parasitic infections. They release chemicals to combat these conditions but not heparin or histamine.
• Monocytes: Monocytes are another type of white blood cell that mature into macrophages and dendritic cells. These cells play a role in the immune system but do not release heparin or histamine.

Answer: Vitamin K

Vitamin K is essential for the production of several proteins involved in blood clotting. These proteins help platelets stick together and form clots to seal wounds and prevent excessive bleeding.

The other options are incorrect:

• Vitamin A: Vitamin A is important for vision, immune function, and cell growth, but it doesn’t directly affect blood clotting.
• Vitamin B: There are several B vitamins, but none of them play a primary role in blood clotting.
• Vitamin C: Vitamin C is an antioxidant that helps with immune function and collagen production, but it’s not essential for blood clotting.

Answer: Factor VIII

Hemophilia A is a genetic disorder caused by a deficiency of clotting factor VIII, leading to impaired blood clotting.

The other options are incorrect:

• Factor VII: While factor VII is involved in the clotting cascade, its absence is not the primary cause of Hemophilia A.
• Factor IX: Deficiency in factor IX causes Hemophilia B, another type of hemophilia with similar symptoms but a different genetic basis.
• Factor X: Factor X is another clotting factor, but its absence is not the main cause of Hemophilia A.

Answer: All of the above

Plasma proteins play a variety of crucial roles in the blood:

• Oxygen transport: While not directly transporting oxygen themselves, plasma proteins like albumin help bind fatty acids that carry some oxygen in the blood.
• Blood buffers: Plasma proteins can act as buffers to help maintain the blood’s pH within a healthy range.
• Exerts osmotic pressure: Plasma proteins, particularly albumin, contribute significantly to the osmotic pressure in blood vessels. This pressure helps maintain fluid balance between the bloodstream and tissues.