MCQs on Human Blood Physiology

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1. What is the primary function of red blood cells (RBCs)?

  • a) Transport carbon dioxide
  • b) Transport oxygen
  • c) Protect against infection
  • d) Produce antibodies

Answer: b) Transport oxygen
Explanation: Red blood cells (RBCs) primarily function to transport oxygen from the lungs to tissues and organs, and return carbon dioxide from tissues to the lungs for exhalation. They contain hemoglobin, which binds oxygen for efficient transport.

2. What is the main component of plasma in blood?

  • a) Red blood cells
  • b) Platelets
  • c) Water
  • d) Leukocytes

Answer: c) Water
Explanation: Plasma, the liquid component of blood, is composed mainly of water (about 90%). The remaining 10% consists of proteins (albumin, globulins, fibrinogen), nutrients, electrolytes, gases, and waste products.

3. What is the normal range of hemoglobin in adult males?

  • a) 10-12 g/dL
  • b) 13-17 g/dL
  • c) 18-20 g/dL
  • d) 8-10 g/dL

Answer: b) 13-17 g/dL
Explanation: In adult males, the normal range of hemoglobin levels is typically 13-17 grams per deciliter (g/dL). Hemoglobin is crucial for oxygen transport and plays a key role in the respiratory system.

4. What is the process of blood clotting known as?

  • a) Hemostasis
  • b) Hematopoiesis
  • c) Erythropoiesis
  • d) Leukopoiesis

Answer: a) Hemostasis
Explanation: Hemostasis is the process that prevents and stops bleeding, involving blood vessel constriction, platelet plug formation, and clotting through fibrin. This mechanism ensures that blood loss is minimized following injury.

5. What is the role of platelets in blood?

  • a) Transport oxygen
  • b) Fight infections
  • c) Facilitate blood clotting
  • d) Remove waste products

Answer: c) Facilitate blood clotting
Explanation: Platelets (thrombocytes) play a crucial role in blood clotting. When blood vessels are damaged, platelets adhere to the injury site and release clotting factors to form a fibrin clot that stops bleeding.

6. What is the function of white blood cells (WBCs)?

  • a) Transport oxygen
  • b) Aid in digestion
  • c) Fight infection and disease
  • d) Carry nutrients

Answer: c) Fight infection and disease
Explanation: White blood cells (WBCs) are part of the immune system and protect the body by fighting infections and foreign substances. They are capable of phagocytosis and producing antibodies to combat pathogens.

7. What is the function of hemoglobin?

  • a) Regulate blood pressure
  • b) Carry oxygen to tissues
  • c) Regulate body temperature
  • d) Initiate clotting process

Answer: b) Carry oxygen to tissues
Explanation: Hemoglobin is a protein found in red blood cells that binds to oxygen in the lungs and transports it to tissues and organs, where it is released for cellular respiration.

8. What is the average lifespan of a red blood cell?

  • a) 120 days
  • b) 60 days
  • c) 45 days
  • d) 30 days

Answer: a) 120 days
Explanation: The average lifespan of a red blood cell is about 120 days. After this period, they are removed from circulation and broken down in the spleen, where their components are recycled.

9. Which organ is primarily responsible for the production of erythropoietin (EPO)?

  • a) Liver
  • b) Kidneys
  • c) Bone marrow
  • d) Heart

Answer: b) Kidneys
Explanation: Erythropoietin (EPO) is primarily produced by the kidneys. It stimulates the production of red blood cells in the bone marrow in response to low oxygen levels in the blood.

10. What is the process of red blood cell production called?

  • a) Hemostasis
  • b) Hematopoiesis
  • c) Erythropoiesis
  • d) Leukopoiesis

Answer: c) Erythropoiesis
Explanation: Erythropoiesis is the process by which new red blood cells are produced in the bone marrow. This process is regulated by erythropoietin (EPO), especially when oxygen levels in the blood are low.

11. Which of the following blood cells are involved in immune response?

  • a) Red blood cells
  • b) Platelets
  • c) White blood cells
  • d) Plasma cells

Answer: c) White blood cells
Explanation: White blood cells (WBCs) are key players in the immune response, fighting infections by identifying and destroying pathogens like bacteria, viruses, and fungi.

12. What type of white blood cell is primarily involved in allergic reactions?

  • a) Neutrophils
  • b) Eosinophils
  • c) Basophils
  • d) Lymphocytes

Answer: b) Eosinophils
Explanation: Eosinophils are a type of white blood cell that play a key role in combating parasitic infections and are involved in allergic reactions by releasing histamine.

13. What is the role of fibrinogen in blood clotting?

  • a) Prevent clot formation
  • b) Dissolve blood clots
  • c) Convert to fibrin to form a clot
  • d) Activate platelets

Answer: c) Convert to fibrin to form a clot
Explanation: Fibrinogen is a plasma protein that, when activated during the clotting process, is converted into fibrin. Fibrin strands form a mesh that traps blood cells, creating a blood clot.

14. Which of the following is an example of a granulocyte?

Answer: b) Neutrophil
Explanation: Neutrophils are a type of granulocyte, which contain granules filled with enzymes. They are the most abundant type of white blood cell and are essential in the defense against bacterial infections.

15. Which of the following statements about the blood type AB is true?

  • a) AB blood type has both anti-A and anti-B antibodies.
  • b) AB blood type can receive blood from any other blood type.
  • c) AB blood type can donate to anyone.
  • d) AB blood type is universal donor.

Answer: b) AB blood type can receive blood from any other blood type.
Explanation: Individuals with blood type AB are considered universal recipients because they do not have antibodies against A or B antigens. They can receive blood from type A, B, AB, or O.

16. Which of the following is a characteristic of O-negative blood?

  • a) Universal plasma donor
  • b) Universal red blood cell donor
  • c) Can only donate to AB-positive
  • d) Has A and B antigens

Answer: b) Universal red blood cell donor
Explanation: O-negative blood is the universal red blood cell donor type because it lacks A, B, and Rh antigens, making it compatible with all blood types for transfusions.

17. What is the normal platelet count in the blood?

  • a) 100,000-150,000/µL
  • b) 150,000-400,000/µL
  • c) 50,000-100,000/µL
  • d) 200,000-500,000/µL

Answer: b) 150,000-400,000/µL
Explanation: The normal platelet count in a healthy adult is generally between 150,000 and 400,000 platelets per microliter of blood. Platelets are essential for blood clotting and wound healing.

18. What is the primary function of the lymphatic system in blood physiology?

  • a) Regulate blood pressure
  • b) Transport oxygen
  • c) Remove waste products
  • d) Drain excess fluid from tissues and return it to the blood

Answer: d) Drain excess fluid from tissues and return it to the blood
Explanation: The lymphatic system helps to return excess tissue fluid (lymph) to the bloodstream, maintain fluid balance, and support immune function.

19. Which of the following is responsible for the "redness" in inflamed tissues?

  • a) Platelets
  • b) White blood cells
  • c) Increased blood flow
  • d) Fibrin

Answer: c) Increased blood flow
Explanation: Inflammation leads to increased blood flow to the affected area, causing redness. This is part of the body’s immune response to injury or infection.

20. What is the primary function of the spleen in blood physiology?

  • a) Filter toxins from the blood
  • b) Produce red blood cells
  • c) Store and filter blood
  • d) Regulate body temperature

Answer: c) Store and filter blood
Explanation: The spleen filters blood, removing old or damaged red blood cells, and stores platelets and white blood cells. It also plays a role in the immune response.

21. What is the primary function of plasma proteins?

  • a) Transport oxygen
  • b) Help in blood clotting
  • c) Provide energy
  • d) Protect against infections

Answer: b) Help in blood clotting
Explanation: Plasma proteins like fibrinogen play an essential role in blood clotting. Other plasma proteins, such as albumin, help maintain osmotic pressure and transport various substances like hormones and nutrients.

22. What type of white blood cell is most abundant in the bloodstream?

  • a) Lymphocytes
  • b) Eosinophils
  • c) Neutrophils
  • d) Monocytes

Answer: c) Neutrophils
Explanation: Neutrophils are the most abundant type of white blood cells in the bloodstream. They are involved in the body's defense mechanisms, particularly in fighting bacterial infections through phagocytosis.

23. What is the major site for the production of blood cells in adults?

  • a) Spleen
  • b) Liver
  • c) Bone marrow
  • d) Kidneys

Answer: c) Bone marrow
Explanation: The bone marrow is the primary site of hematopoiesis in adults, where the formation of red blood cells, white blood cells, and platelets takes place.

24. What is the Rh factor in blood typing?

  • a) The presence of antibodies
  • b) A type of white blood cell
  • c) An antigen present on red blood cells
  • d) A protein involved in clotting

Answer: c) An antigen present on red blood cells
Explanation: The Rh factor is an antigen present on the surface of red blood cells. People who have this antigen are Rh-positive (Rh+), while those without it are Rh-negative (Rh-).

25. What is the function of lymphocytes in blood physiology?

  • a) Transport oxygen
  • b) Defend against infection
  • c) Promote clotting
  • d) Remove waste products

Answer: b) Defend against infection
Explanation: Lymphocytes are a type of white blood cell involved in the immune response. They help defend the body against infections by recognizing and responding to foreign pathogens, including viruses and bacteria.

26. What type of blood cell is primarily involved in transporting oxygen?

  • a) Platelets
  • b) Red blood cells
  • c) White blood cells
  • d) Plasma cells

Answer: b) Red blood cells
Explanation: Red blood cells (RBCs) are specialized for oxygen transport. They contain hemoglobin, a protein that binds oxygen in the lungs and releases it to tissues and organs for cellular respiration.

27. What is the role of albumin in the blood?

  • a) Blood clotting
  • b) Immune defense
  • c) Regulate osmotic pressure
  • d) Transport oxygen

Answer: c) Regulate osmotic pressure
Explanation: Albumin is a plasma protein that helps maintain osmotic pressure in blood, ensuring that fluid remains within the blood vessels and preventing excessive fluid from leaking into surrounding tissues.

28. Which of the following conditions is associated with low red blood cell count?

Answer: b) Anemia
Explanation: Anemia is a condition characterized by a low red blood cell count or insufficient hemoglobin, leading to reduced oxygen delivery to tissues. It can result from various causes, including iron deficiency or chronic disease.

29. What is the term used for the process of white blood cell formation?

  • a) Erythropoiesis
  • b) Leukopoiesis
  • c) Hematopoiesis
  • d) Thrombopoiesis

Answer: b) Leukopoiesis
Explanation: Leukopoiesis is the process of white blood cell formation. It occurs primarily in the bone marrow and involves the differentiation of stem cells into various types of leukocytes, including neutrophils, lymphocytes, and monocytes.

30. Which blood group is known as the universal donor for red blood cells?

  • a) AB-positive
  • b) O-negative
  • c) A-positive
  • d) B-negative

Answer: b) O-negative
Explanation: O-negative blood is considered the universal donor for red blood cells because it lacks A, B, and Rh antigens, making it compatible with all other blood types for transfusions.

31. What is the function of the enzyme thrombin in blood clotting?

  • a) Breaks down fibrinogen into fibrin
  • b) Converts prothrombin into thrombin
  • c) Dissolves the clot
  • d) Activates white blood cells

Answer: a) Breaks down fibrinogen into fibrin
Explanation: Thrombin is a key enzyme in the clotting process. It converts fibrinogen, a soluble plasma protein, into fibrin, which forms the mesh-like structure of a blood clot.

32. What is the primary role of neutrophils?

Answer: c) Phagocytosis of pathogens
Explanation: Neutrophils are the first line of defense in the immune system. They are involved in the phagocytosis (ingestion) and destruction of bacteria and other pathogens, playing a key role in the inflammatory response.

33. What is the main function of the spleen in blood physiology?

  • a) Produce blood cells
  • b) Filter and store blood
  • c) Synthesize clotting factors
  • d) Regulate body temperature

Answer: b) Filter and store blood
Explanation: The spleen filters old and damaged red blood cells from the blood and stores platelets and white blood cells. It also plays a role in the immune response.

34. Which of the following is a characteristic of hemophilia?

  • a) Increased platelet count
  • b) Defective clotting factor
  • c) Excessive white blood cell production
  • d) High red blood cell count

Answer: b) Defective clotting factor
Explanation: Hemophilia is a genetic disorder characterized by defective clotting factors, leading to difficulty forming blood clots and an increased risk of bleeding following injury.

35. What is the process of red blood cell destruction called?

  • a) Erythropoiesis
  • b) Hemolysis
  • c) Leukopoiesis
  • d) Phagocytosis

Answer: b) Hemolysis
Explanation: Hemolysis refers to the breakdown of red blood cells, which occurs when they reach the end of their lifespan (about 120 days) or are damaged. This process releases hemoglobin into the bloodstream.

36. Which vitamin is essential for blood clotting?

  • a) Vitamin A
  • b) Vitamin D
  • c) Vitamin K
  • d) Vitamin C

Answer: c) Vitamin K
Explanation: Vitamin K is essential for the synthesis of clotting factors in the liver. It plays a vital role in the coagulation cascade, which helps form blood clots to prevent excessive bleeding.

37. What does the term "hematocrit" refer to?

  • a) The number of white blood cells
  • b) The percentage of blood volume made up of red blood cells
  • c) The amount of oxygen carried by hemoglobin
  • d) The total amount of plasma proteins in blood

Answer: b) The percentage of blood volume made up of red blood cells
Explanation: Hematocrit refers to the proportion of red blood cells in the blood. It is expressed as a percentage and is a key measure of blood's oxygen-carrying capacity.

38. What is the average lifespan of platelets?

  • a) 7-10 days
  • b) 120 days
  • c) 5-7 days
  • d) 1-2 weeks

Answer: a) 7-10 days
Explanation: Platelets have a lifespan of approximately 7-10 days. After this period, they are removed from circulation and degraded by the liver and spleen.

39. What role does the bone marrow play in blood physiology?

  • a) Filters blood
  • b) Stores iron
  • c) Produces blood cells
  • d) Regulates blood pressure

Answer: c) Produces blood cells
Explanation: Bone marrow is the primary site of blood cell production (hematopoiesis). It generates red blood cells, white blood cells, and platelets, which are essential for various bodily functions like oxygen transport and immune defense.

40. Which blood group is considered the universal plasma donor?

  • a) AB-negative
  • b) O-positive
  • c) AB-positive
  • d) O-negative

Answer: a) AB-negative
Explanation: AB-negative plasma is considered universal donor plasma because it does not contain anti-A or anti-B antibodies, making it safe for transfusion to individuals with any blood type.

41. What is the role of the enzyme plasmin in blood physiology?

  • a) Converts fibrinogen to fibrin
  • b) Breaks down fibrin in clots
  • c) Activates thrombin
  • d) Converts prothrombin to thrombin

Answer: b) Breaks down fibrin in clots
Explanation: Plasmin is an enzyme involved in fibrinolysis, the process of breaking down fibrin clots. It helps remove clots after they have served their purpose in the healing process.

42. Which of the following hormones regulates red blood cell production?

  • a) Insulin
  • b) Thyroxine
  • c) Erythropoietin
  • d) Aldosterone

Answer: c) Erythropoietin
Explanation: Erythropoietin is a hormone produced primarily by the kidneys that stimulates the production of red blood cells in the bone marrow in response to low oxygen levels in the blood.

43. What is the function of hemoglobin in red blood cells?

  • a) Carry carbon dioxide
  • b) Regulate pH
  • c) Carry oxygen
  • d) Fight infections

Answer: c) Carry oxygen
Explanation: Hemoglobin is a protein found in red blood cells responsible for binding oxygen in the lungs and transporting it through the bloodstream to tissues and organs for cellular respiration.

44. What condition is characterized by an increase in the number of red blood cells?

  • a) Polycythemia
  • b) Leukopenia
  • c) Anemia
  • d) Hemophilia

Answer: a) Polycythemia
Explanation: Polycythemia is a condition where there is an increase in the number of red blood cells in the blood, which can result in increased blood viscosity and a higher risk of clot formation.

45. What is the primary function of platelets?

  • a) Carry oxygen
  • b) Defend against infections
  • c) Promote blood clotting
  • d) Regulate blood pressure

Answer: c) Promote blood clotting
Explanation: Platelets are small cell fragments that play a crucial role in blood clotting. They adhere to the site of injury, aggregate, and activate the clotting cascade to form a stable clot.

46. What is the primary site of erythropoiesis during fetal development?

  • a) Bone marrow
  • b) Liver
  • c) Spleen
  • d) Kidneys

Answer: b) Liver
Explanation: During fetal development, the liver is the primary site of erythropoiesis (red blood cell production). Later, bone marrow takes over the responsibility after birth.

47. What is the process by which blood cells are formed from stem cells in the bone marrow?

  • a) Hemostasis
  • b) Hematopoiesis
  • c) Leukopoiesis
  • d) Erythropoiesis

Answer: b) Hematopoiesis
Explanation: Hematopoiesis is the process by which blood cells are produced from stem cells in the bone marrow. This includes the formation of red blood cells, white blood cells, and platelets.

48. What is the function of the ABO blood group system?

  • a) To regulate clotting
  • b) To transport nutrients
  • c) To categorize red blood cell types
  • d) To increase oxygen affinity

Answer: c) To categorize red blood cell types
Explanation: The ABO blood group system classifies blood based on the presence or absence of antigens A and B on red blood cells. The major blood types are A, B, AB, and O.

49. Which protein is essential for blood clot formation?

  • a) Collagen
  • b) Fibrinogen
  • c) Hemoglobin
  • d) Albumin

Answer: b) Fibrinogen
Explanation: Fibrinogen is a plasma protein that is converted into fibrin during the clotting process. Fibrin forms the mesh-like structure of a blood clot, which helps to seal wounds and prevent further bleeding.

50. What is the role of the lymphatic system in blood physiology?

  • a) Remove carbon dioxide
  • b) Transport oxygen
  • c) Drain excess fluids and waste products
  • d) Store red blood cells

Answer: c) Drain excess fluids and waste products
Explanation: The lymphatic system helps return excess interstitial fluid to the bloodstream and plays a role in immune defense by filtering pathogens and foreign particles from the lymph.

51. Which of the following blood cells are involved in adaptive immunity?

  • a) Erythrocytes
  • b) Neutrophils
  • c) Lymphocytes
  • d) Platelets

Answer: c) Lymphocytes
Explanation: Lymphocytes, particularly T cells and B cells, are involved in adaptive immunity. They recognize specific pathogens and mount an immune response to fight infections, including the production of antibodies.

52. What is the major function of fibrin in clot formation?

  • a) To strengthen blood vessel walls
  • b) To convert prothrombin into thrombin
  • c) To form the framework of a blood clot
  • d) To stimulate platelet aggregation

Answer: c) To form the framework of a blood clot
Explanation: Fibrin forms the structural framework of a blood clot. It is the end product of the clotting cascade, where it forms long strands that intertwine to stabilize the clot at the injury site.

53. What is the average volume of blood in an adult human body?

  • a) 3-4 liters
  • b) 5-6 liters
  • c) 7-8 liters
  • d) 10-12 liters

Answer: b) 5-6 liters
Explanation: The average volume of blood in an adult human body is approximately 5 to 6 liters. This volume varies depending on the individual's size, gender, and other factors.

54. What is the process of removing old or damaged red blood cells called?

  • a) Hematopoiesis
  • b) Hemolysis
  • c) Phagocytosis
  • d) Erythropoiesis

Answer: b) Hemolysis
Explanation: Hemolysis refers to the destruction of old or damaged red blood cells. This process primarily occurs in the spleen, where macrophages engulf and break down red blood cells.

55. Which of the following conditions is characterized by excessive bleeding due to the lack of clotting factors?

  • a) Hemophilia
  • b) Sickle cell anemia
  • c) Polycythemia
  • d) Leukemia

Answer: a) Hemophilia
Explanation: Hemophilia is a genetic disorder where the blood does not clot properly due to a deficiency or dysfunction of clotting factors, leading to excessive bleeding and difficulty in wound healing.

56. Which blood type is known as the universal plasma recipient?

  • a) O-positive
  • b) AB-negative
  • c) AB-positive
  • d) O-negative

Answer: c) AB-positive
Explanation: AB-positive individuals are considered universal plasma recipients because their blood contains both A and B antigens, and they do not have antibodies against A, B, or Rh antigens.

57. What is the primary function of the bone marrow in blood physiology?

  • a) Filter waste products
  • b) Produce hormones
  • c) Produce blood cells
  • d) Store iron

Answer: c) Produce blood cells
Explanation: The bone marrow is the primary site of blood cell production (hematopoiesis), producing red blood cells, white blood cells, and platelets, all of which are essential for various bodily functions.

58. Which of the following is the function of the hormone hepcidin?

  • a) Increase red blood cell production
  • b) Regulate iron homeostasis
  • c) Increase blood pressure
  • d) Stimulate platelet aggregation

Answer: b) Regulate iron homeostasis
Explanation: Hepcidin is a liver-produced hormone that regulates iron levels in the body by inhibiting iron absorption in the gut and reducing the release of stored iron from cells.

59. Which of the following is the most common cause of anemia?

  • a) Vitamin B12 deficiency
  • b) Iron deficiency
  • c) Folate deficiency
  • d) Chronic blood loss

Answer: b) Iron deficiency
Explanation: Iron deficiency is the most common cause of anemia. It occurs when the body lacks sufficient iron to produce hemoglobin, leading to reduced oxygen-carrying capacity of the blood.

60. What is the role of the protein thrombin in coagulation?

  • a) It forms fibrin from fibrinogen
  • b) It converts plasminogen to plasmin
  • c) It dissolves clots
  • d) It activates the clotting factors

Answer: a) It forms fibrin from fibrinogen
Explanation: Thrombin plays a crucial role in blood clotting by converting fibrinogen, a soluble plasma protein, into fibrin, which forms the structural mesh of a clot.


61. Which blood cell type is responsible for fighting bacterial infections?

  • a) Eosinophils
  • b) Neutrophils
  • c) Basophils
  • d) Lymphocytes

Answer: b) Neutrophils
Explanation: Neutrophils are the most abundant type of white blood cells and are the first responders to bacterial infections. They engulf and digest bacteria through a process called phagocytosis.

62. What is the function of the spleen in blood physiology?

  • a) Produce red blood cells
  • b) Store platelets
  • c) Filter blood and remove old red blood cells
  • d) Produce white blood cells

Answer: c) Filter blood and remove old red blood cells
Explanation: The spleen filters the blood, removing old or damaged red blood cells and recycling iron. It also stores platelets and plays a role in immune responses.

63. Which vitamin is essential for the synthesis of clotting factors in the liver?

  • a) Vitamin A
  • b) Vitamin B12
  • c) Vitamin D
  • d) Vitamin K

Answer: d) Vitamin K
Explanation: Vitamin K is crucial for the synthesis of clotting factors in the liver. Without it, blood clotting is impaired, leading to excessive bleeding. Vitamin K is also involved in bone health.

64. What is the function of antibodies in blood physiology?

  • a) Transport oxygen
  • b) Facilitate blood clotting
  • c) Neutralize pathogens
  • d) Aid in digestion

Answer: c) Neutralize pathogens
Explanation: Antibodies are proteins produced by B lymphocytes in response to foreign invaders like bacteria, viruses, and toxins. They neutralize or tag pathogens for destruction by other immune cells.

65. What is the term for the increase in white blood cells due to infection or inflammation?

Answer: b) Leukocytosis
Explanation: Leukocytosis refers to an elevated white blood cell count, typically a response to infection, inflammation, or certain medications. It helps the body fight off infections and disease.

66. What is the primary role of the kidneys in blood physiology?

  • a) Filter blood and excrete waste
  • b) Produce red blood cells
  • c) Produce clotting factors
  • d) Regulate blood pressure

Answer: a) Filter blood and excrete waste
Explanation: The kidneys filter waste products from the blood, regulate fluid and electrolyte balance, and help in the removal of excess substances, maintaining homeostasis in the body.

67. Which of the following conditions results from the inability of the body to clot properly?

Answer: b) Hemophilia
Explanation: Hemophilia is a genetic disorder where blood doesn't clot properly due to the lack of clotting factors. This can lead to spontaneous bleeding and difficulty in healing wounds.

68. What is the primary function of erythropoietin?

  • a) Stimulate platelet production
  • b) Stimulate red blood cell production
  • c) Stimulate white blood cell production
  • d) Regulate iron absorption

Answer: b) Stimulate red blood cell production
Explanation: Erythropoietin is a hormone primarily produced by the kidneys in response to low oxygen levels in the blood. It stimulates the bone marrow to produce more red blood cells.

69. Which of the following is the result of a low white blood cell count?

Answer: a) Leukopenia
Explanation: Leukopenia refers to a decrease in white blood cell count, often resulting from viral infections, chemotherapy, or autoimmune diseases, leading to increased susceptibility to infections.

70. What is the function of the protein albumin in the blood?

  • a) Carry oxygen
  • b) Maintain blood volume and pressure
  • c) Form blood clots
  • d) Transport lipids

Answer: b) Maintain blood volume and pressure
Explanation: Albumin is the most abundant plasma protein and plays a critical role in maintaining the osmotic pressure of blood, thereby helping to regulate blood volume and pressure.

71. Which factor is crucial for the formation of a stable blood clot?

  • a) Prothrombin
  • b) Plasminogen
  • c) Fibrinogen
  • d) Hemoglobin

Answer: c) Fibrinogen
Explanation: Fibrinogen is a plasma protein that is converted into fibrin during the coagulation cascade. Fibrin forms a mesh that stabilizes the clot and prevents further bleeding.

72. Which cell type is responsible for the immune response to viruses?

  • a) Neutrophils
  • b) Eosinophils
  • c) T lymphocytes
  • d) Platelets

Answer: c) T lymphocytes
Explanation: T lymphocytes (T cells) are responsible for the cell-mediated immune response to viruses and other pathogens. They directly destroy infected cells and activate other immune cells.

73. What is the main function of the circulatory system in blood physiology?

  • a) Transport oxygen and nutrients to tissues
  • b) Destroy pathogens
  • c) Regulate body temperature
  • d) Filter waste products

Answer: a) Transport oxygen and nutrients to tissues
Explanation: The circulatory system transports oxygen, nutrients, hormones, and waste products throughout the body. It ensures the delivery of essential substances to tissues and organs while removing metabolic wastes.

74. Which of the following can lead to polycythemia?

  • a) Chronic hypoxia
  • b) Vitamin B12 deficiency
  • c) Leukemia
  • d) Hemophilia

Answer: a) Chronic hypoxia
Explanation: Polycythemia, characterized by an increased number of red blood cells, can result from chronic hypoxia, such as in people living at high altitudes, as the body compensates for low oxygen levels.

75. What is the term for low platelet count?

Answer: b) Thrombocytopenia
Explanation: Thrombocytopenia refers to a condition where the platelet count is low, which can lead to increased bleeding risk and difficulty in blood clotting.

76. What is the function of the hemoglobin molecule?

  • a) Transport oxygen
  • b) Stimulate blood clotting
  • c) Regulate blood pressure
  • d) Fight infections

Answer: a) Transport oxygen
Explanation: Hemoglobin is a protein in red blood cells that binds oxygen in the lungs and carries it to the tissues, where it is released for cellular use in metabolism.

77. What is the term for excessive blood clotting?

Answer: b) Thrombosis
Explanation: Thrombosis refers to the formation of a blood clot (thrombus) within a blood vessel. This can obstruct blood flow, leading to conditions such as deep vein thrombosis or pulmonary embolism.

78. What condition occurs when there is an abnormally low level of hemoglobin?

Answer: b) Anemia
Explanation: Anemia is a condition where the hemoglobin level is too low to meet the body's oxygen demands. It can result from iron deficiency, chronic disease, or genetic disorders.

79. Which organ is primarily responsible for filtering blood and removing waste products?

  • a) Heart
  • b) Spleen
  • c) Kidney
  • d) Liver

Answer: c) Kidney
Explanation: The kidneys filter blood to remove waste products, excess substances, and toxins. They also regulate electrolyte balance, fluid levels, and blood pressure.

80. What role does the liver play in blood physiology?

  • a) Synthesize clotting factors
  • b) Filter blood cells
  • c) Store iron
  • d) All of the above

Answer: d) All of the above
Explanation: The liver synthesizes clotting factors, filters out waste products, stores iron, and plays a central role in metabolism and detoxification, maintaining the health of the blood.

81. What is the primary component of plasma in the blood?

  • a) Red blood cells
  • b) Platelets
  • c) Water
  • d) White blood cells

Answer: c) Water
Explanation: Plasma is the liquid portion of blood and is primarily composed of water (about 90%). It also contains proteins, electrolytes, nutrients, hormones, and waste products.

82. Which of the following describes the primary role of hemoglobin?

  • a) Fight infections
  • b) Transport oxygen
  • c) Form clots
  • d) Stimulate the immune system

Answer: b) Transport oxygen
Explanation: Hemoglobin is a protein in red blood cells that binds oxygen in the lungs and carries it through the bloodstream to tissues and organs, ensuring adequate oxygenation.

83. What is the term for the condition where the body has an insufficient amount of oxygen in the tissues?

  • a) Hypoxia
  • b) Hypercapnia
  • c) Hyperoxia
  • d) Hypovolemia

Answer: a) Hypoxia
Explanation: Hypoxia refers to a condition where tissues in the body do not receive enough oxygen, which can result from conditions such as anemia or respiratory failure.

84. What blood type is considered the universal donor for red blood cells?

  • a) Type A
  • b) Type B
  • c) Type AB
  • d) Type O

Answer: d) Type O
Explanation: Type O negative blood is considered the universal donor for red blood cells because it lacks A, B, and Rh antigens, minimizing the risk of an immune response during transfusion.

85. What is the major function of platelets in blood?

  • a) Carry oxygen
  • b) Regulate blood pressure
  • c) Form blood clots
  • d) Transport nutrients

Answer: c) Form blood clots
Explanation: Platelets are essential for blood clotting. When blood vessels are injured, platelets adhere to the site of injury, releasing clotting factors that help form a stable clot to prevent further bleeding.

86. Which condition is associated with a decrease in red blood cell production?

Answer: c) Anemia
Explanation: Anemia occurs when there is a deficiency in the number or quality of red blood cells, leading to reduced oxygen delivery to tissues. Causes include iron deficiency, vitamin B12 deficiency, or bone marrow disorders.

87. Which of the following describes the role of fibrinogen in the blood?

  • a) It helps with oxygen transport.
  • b) It plays a key role in blood clot formation.
  • c) It fights infections.
  • d) It regulates blood pressure.

Answer: b) It plays a key role in blood clot formation.
Explanation: Fibrinogen is a plasma protein that, when activated, forms fibrin strands. These strands create a mesh that stabilizes blood clots, preventing further bleeding during injury.

88. Which part of the bone marrow is primarily responsible for the production of blood cells?

  • a) Yellow marrow
  • b) Red marrow
  • c) Epiphysis
  • d) Diaphysis

Answer: b) Red marrow
Explanation: Red bone marrow is the primary site of hematopoiesis, the process by which blood cells (red blood cells, white blood cells, and platelets) are produced. It is found mainly in flat bones such as the sternum and pelvis.

89. What is the primary cause of sickle cell anemia?

  • a) Iron deficiency
  • b) Genetic mutation in hemoglobin
  • c) Bacterial infection
  • d) Vitamin B12 deficiency

Answer: b) Genetic mutation in hemoglobin
Explanation: Sickle cell anemia is caused by a genetic mutation in the hemoglobin gene, resulting in abnormal hemoglobin (HbS). These abnormally shaped red blood cells block blood flow, leading to pain and organ damage.

90. What is the process by which white blood cells engulf and digest pathogens?

  • a) Phagocytosis
  • b) Hemolysis
  • c) Coagulation
  • d) Hemostasis

Answer: a) Phagocytosis
Explanation: Phagocytosis is the process by which certain white blood cells (such as neutrophils and macrophages) engulf and digest pathogens, dead cells, and foreign particles to protect the body from infections.

91. Which of the following is a major component of the body's immune response?

  • a) Erythropoietin
  • b) Antibodies
  • c) Platelets
  • d) Hemoglobin

Answer: b) Antibodies
Explanation: Antibodies are proteins produced by the immune system that specifically recognize and neutralize foreign invaders like viruses and bacteria. They are a critical part of the adaptive immune response.

92. Which of the following is the primary function of the lymphatic system in blood physiology?

  • a) Transport oxygen
  • b) Remove waste products from the blood
  • c) Produce red blood cells
  • d) Drain excess fluid from tissues

Answer: d) Drain excess fluid from tissues
Explanation: The lymphatic system is responsible for draining excess fluid from tissues and returning it to the bloodstream. It also plays a key role in immune surveillance and fighting infections.

93. Which factor increases the viscosity of blood?

  • a) Increase in red blood cell count
  • b) Decrease in white blood cell count
  • c) Decrease in plasma proteins
  • d) Increase in platelets

Answer: a) Increase in red blood cell count
Explanation: An increase in the number of red blood cells (as in polycythemia) increases the viscosity of blood, making it thicker. This can affect blood flow and increase the risk of clot formation.

94. What is the role of the enzyme plasmin in blood clotting?

  • a) Activate clotting factors
  • b) Break down fibrin to dissolve clots
  • c) Produce red blood cells
  • d) Stimulate platelet aggregation

Answer: b) Break down fibrin to dissolve clots
Explanation: Plasmin is an enzyme that breaks down fibrin, the protein that forms blood clots. This process, called fibrinolysis, helps to dissolve clots once healing has occurred.

95. Which of the following best describes the term hematopoiesis?

  • a) The destruction of old blood cells
  • b) The production of blood cells
  • c) The process of blood clotting
  • d) The movement of blood cells through vessels

Answer: b) The production of blood cells
Explanation: Hematopoiesis is the process of blood cell formation, which occurs in the bone marrow. This includes the production of red blood cells, white blood cells, and platelets.

96. Which hormone stimulates the production of red blood cells?

  • a) Cortisol
  • b) Erythropoietin
  • c) Insulin
  • d) Thyroid hormone

Answer: b) Erythropoietin
Explanation: Erythropoietin is a hormone primarily produced by the kidneys in response to low oxygen levels. It stimulates the bone marrow to increase the production of red blood cells.

97. Which blood component is responsible for preventing excessive bleeding?

  • a) Red blood cells
  • b) White blood cells
  • c) Platelets
  • d) Plasma proteins

Answer: c) Platelets
Explanation: Platelets are small cell fragments that play a key role in hemostasis by forming a plug at injury sites and releasing clotting factors to stop bleeding.

98. What condition is characterized by abnormally high levels of iron in the blood?

  • a) Hemochromatosis
  • b) Sickle cell anemia
  • c) Iron deficiency anemia
  • d) Leukemia

Answer: a) Hemochromatosis
Explanation: Hemochromatosis is a genetic disorder that leads to excessive absorption of iron from food. This iron accumulates in organs like the liver, heart, and pancreas, potentially causing damage.

99. Which component of blood is involved in immune defense against pathogens?

Answer: c) Leukocytes
Explanation: Leukocytes (white blood cells) are the key players in the immune system. They defend the body against infections by identifying and attacking pathogens such as bacteria and viruses.

100. Which of the following is a function of plasma in blood?

  • a) Transport oxygen
  • b) Carry nutrients and waste
  • c) Fight infections
  • d) Form blood clots

Answer: b) Carry nutrients and waste
Explanation: Plasma is responsible for transporting nutrients, hormones, waste products, and proteins like clotting factors throughout the body. It also helps maintain blood pressure and volume.

 

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