Question 1

Fetal hemoglobin consists of which of the following chains?

Accepted Answer

Fetal hemoglobin consists of two alpha chains and two gamma chains, so the correct option is B which has alpha and gamma chains.

Question 2

What percentage of hemoglobin is synthesized in the reticulocyte stage?

Accepted Answer

C

Question 3

Each hemoglobin molecule consists of heme structures.

Accepted Answer

Each hemoglobin molecule consists of four heme structures.

Question 4

Which of the following factors will result in an immediate increase in oxygen delivery to the tissues?

Accepted Answer

Increased 2,3-DPG (2,3-diphosphoglycerate) in red blood cells decreases hemoglobin's affinity for oxygen, thereby facilitating the release of oxygen to the tissues. This mechanism is a way the body can adapt to ensure that tissues receive more oxygen under conditions where they might need it, such as during periods of low oxygen availability or increased metabolic demand.

Question 5

How many genes are responsible for the productions of alpha chains?

Accepted Answer

The answer of How many genes are responsible for the...

Question 6

Physiologic conditions in the body that can decrease hemoglobin's oxygen affinity include:

Accepted Answer

Increased body temperature can cause a decrease in hemoglobin's oxygen affinity, which is known as the Bohr effect. This is because increased temperature promotes the release of oxygen from hemoglobin to the tissues that need it.

Answer: D
 The presence of abnormal hemoglobins, such as sickle cell hemoglobin, can cause a decrease in oxygen affinity due to changes in the structure of the protein. This can lead to oxygen not binding as well to the hemoglobin molecule, which can be detrimental to oxygen transport in the body.

Therefore, the correct answer is C and D.

Question 7

____may be seen in intravascular hemolysis but not in extravascular hemolysis.

Accepted Answer

Hemoglobinuria is the presence of free hemoglobin in the urine, which occurs when an excessive amount of red blood cells are destroyed within the blood vessels and the released hemoglobin is filtered through the kidneys. This is a characteristic feature of intravascular hemolysis, whereas extravascular hemolysis typically results in increased bilirubin levels, splenomegaly, and increased LDH. Therefore, choice A is the correct answer.

Question 8

Abnormal hemoglobins have a lower affinity for oxygen.

Accepted Answer

The answer of Abnormal hemoglobins have a lower affinity for...

Question 9

When iron is present in an oxidized state, as Fe⁺³ or ferric iron, the resulting hemoglobin is known as:

Accepted Answer

Methemoglobin is formed when iron is present in the oxidized ferric state (Fe3+) instead of the reduced ferrous state (Fe2+) in hemoglobin. This alteration in iron prevents the binding of oxygen to the heme group, resulting in a decrease in oxygen-carrying capacity. Carboxyhemoglobin is formed when hemoglobin binds to carbon monoxide, sulfhemoglobin is formed when a sulfur atom is added to the heme group, and deoxyhemoglobin is formed when oxygen is released from the heme group. None of these are specifically related to the presence of oxidized ferric iron in hemoglobin.

Question 10

Hemoglobin begins to be synthesized at the polychromatophilic stage of red cell development.

Accepted Answer

Hemoglobin synthesis begins during the polychromatophilic stage, which is the stage where the red blood cell gains its characteristic pink color due to the presence of hemoglobin.

Question 11

Which of the following clinical conditions is a definitive sign of intravascular lysis?

Accepted Answer

Hemoglobinuria is the presence of free hemoglobin in the urine, which is a definitive sign of intravascular lysis as it indicates the destruction of red blood cells and release of hemoglobin into the bloodstream. Bilirubinemia may also be present in intravascular lysis, but it is not a definitive sign as it can also occur in other conditions such as liver disease. Decreased RBC count and elevated LDH may suggest intravascular lysis, but they are not definitive signs.

Question 12

The hemoglobin molecule will either hold onto or release oxygen depending on the:

Accepted Answer

The relationship between the pulmonary and venous circulations determines whether hemoglobin will hold onto or release oxygen. When oxygen levels are high in the lungs, hemoglobin will bind to oxygen and carry it to oxygen-deprived tissues. When oxygen levels are low in tissues, hemoglobin will release oxygen for use by cells.

Question 13

Which organ(s) is the most affected during extravascular lysis?

Accepted Answer

Extravascular lysis primarily occurs in the liver and spleen, where red blood cells are destroyed and their components are recycled. The breakdown of excessive red blood cells may cause liver and spleen enlargement, leading to anemia and jaundice.

Question 14

Which of the following abnormal hemoglobins will result in a cyanotic condition?

Accepted Answer

Hemoglobin M is an abnormal hemoglobin that can cause cyanosis. This is because hemoglobin M cannot bind oxygen effectively, resulting in decreased oxygen saturation in the blood, which can lead to a bluish tint to the skin and tissues. Sulfhemoglobin and cyanmethemoglobin are also abnormal hemoglobins, but they do not typically cause cyanosis. Hemoglobin F is a normal hemoglobin present in fetal circulation and does not cause cyanosis.

Question 15

What is the term used to define the process by which the bone marrow responds to anemia-induced stress?

Accepted Answer

The term used to define the process by which the bone marrow responds to anemia-induced stress is erythroid hyperplasia, which refers to an increase in the number of red blood cell precursors in the bone marrow in response to decreased oxygen-carrying capacity of the blood. Ineffective erythropoiesis refers to a condition in which the bone marrow produces red blood cells that are defective and/or have a shortened lifespan, while aplastic anemia is a rare disorder characterized by a deficiency in all types of blood cells due to bone marrow failure. Medullary erythropoiesis refers to the production of red blood cells within the bone marrow, which is a normal process.

Question 16

Which of the following is not an embryonic hemoglobin?

Accepted Answer

The answer of Which of the following is not an...

Question 17

Intrinsic red cell defects that can lead to hemolysis include:

Accepted Answer

Intrinsic red cell defects that can lead to hemolysis are inherited deficiencies, which can include hemoglobinopathies (such as sickle cell disease) and enzyme deficiencies (such as G6PD deficiency). Environmental effects and a shift in pH can both contribute to hemolysis, but they are not intrinsic red cell defects.

Question 18

90% of in vivo hemolysis is intravascular.

Accepted Answer

In vivo hemolysis is primarily extravascular, occurring in the spleen, liver, and bone marrow, with only a small percentage being intravascular.

Question 19

Oxygen delivery is the primary purpose of hemoglobin.

Accepted Answer

Hemoglobin is a protein found in red blood cells that binds to oxygen molecules and delivers them to tissues throughout the body. This is its primary function.

Question 20

Epsilon and zeta chains are part of which of the following hemoglobins?

Accepted Answer

Hemoglobin Portland is characterized by the presence of two epsilon (ε) and two zeta (ζ) chains, distinguishing it from other types of hemoglobin which do not contain these chains.

Quiz 4: Hemoglobin Function and Principles of Hemolysis