Blood (Anatomy and Physiology) Practice Questions

54 multiple-choice questions on Blood for paramedic and EMT students, from Chapter 8 (Anatomy and Physiology). Read each question, pick your answer, then tap Show answer to check it and read the explanation.

54 practice questions

1. Plasma makes up about what percentage of blood volume?

   1. A. 25%
   2. B. 55%
   3. C. 10%
   4. D. 45%
   Show answer

   Answer: B. 55%

   Plasma is about 55%. The formed elements (red cells, white cells, and platelets) are about 45%.

2. Which blood cells carry oxygen?

   1. A. Leukocytes
   2. B. Lymphocytes
   3. C. Erythrocytes
   4. D. Thrombocytes
   Show answer

   Answer: C. Erythrocytes

   Red blood cells carry oxygen on hemoglobin.

3. Each hemoglobin molecule can carry up to how many oxygen molecules?

   1. A. 6
   2. B. 2
   3. C. 4
   4. D. 8
   Show answer

   Answer: C. 4

   A hemoglobin molecule has 4 binding sites. Pulse oximetry measures the percentage of those sites that are filled.

4. Most oxygen in the blood is transported:

   1. A. Attached to platelets
   2. B. As bicarbonate
   3. C. Bound to hemoglobin
   4. D. Dissolved in plasma
   Show answer

   Answer: C. Bound to hemoglobin

   About 98% is bound to hemoglobin. Only a small amount dissolves in plasma.

5. Which white blood cell is most common and first to respond to bacterial infection?

   1. A. Eosinophil
   2. B. Basophil
   3. C. Neutrophil
   4. D. Lymphocyte
   Show answer

   Answer: C. Neutrophil

   Neutrophils engulf bacteria. Eosinophils rise in allergies and parasitic infections.

6. The main role of platelets is:

   1. A. Fighting infection
   2. B. Clotting
   3. C. Producing antibodies
   4. D. Carrying CO2
   Show answer

   Answer: B. Clotting

   Platelets clump into a plug and start the clotting cascade.

7. The protein strands that form the mesh of a blood clot are:

   1. A. Hemoglobin
   2. B. Albumin
   3. C. Fibrin
   4. D. Globulin
   Show answer

   Answer: C. Fibrin

   Thrombin converts fibrinogen into fibrin, which traps cells to form the clot.

8. Which blood type is considered the universal donor?

   1. A. B positive
   2. B. AB positive
   3. C. O negative
   4. D. A negative
   Show answer

   Answer: C. O negative

   O negative has no A, B, or Rh antigens. AB positive is the universal recipient.

9. Normal adult blood volume is approximately:

   1. A. 100 mL/kg
   2. B. 35 mL/kg
   3. C. 70 mL/kg
   4. D. 150 mL/kg
   Show answer

   Answer: C. 70 mL/kg

   About 70 mL/kg, or 5-6 L in an average adult.

10. The primary functions of blood include all EXCEPT:

    1. A. Production of digestive enzymes
    2. B. Protection through clotting and immunity
    3. C. Transport of oxygen and nutrients
    4. D. Regulation of temperature and pH
    Show answer

    Answer: A. Production of digestive enzymes

    Blood is a connective tissue with transport and defense roles.

11. The formed elements of blood are:

    1. A. Glucose, lipids, and hormones
    2. B. Red cells, white cells, platelets
    3. C. Albumin, globulins, fibrinogen
    4. D. Plasma water and electrolytes
    Show answer

    Answer: B. Red cells, white cells, platelets

    They account for roughly 45 percent of blood volume.

12. Hematocrit measures:

    1. A. Ratio of plasma to platelets
    2. B. Hemoglobin concentration per deciliter
    3. C. Percentage of white cells in blood
    4. D. Percent of blood volume that is RBCs
    Show answer

    Answer: D. Percent of blood volume that is RBCs

    It falls with bleeding once fluid shifts occur.

13. Red blood cells are produced in the:

    1. A. The liver and spleen
    2. B. Red bone marrow
    3. C. Lymph nodes
    4. D. The thymus gland
    Show answer

    Answer: B. Red bone marrow

    The kidney hormone erythropoietin stimulates production.

14. The average lifespan of a red blood cell is about:

    1. A. 10 days
    2. B. 1 year
    3. C. 30 days
    4. D. 120 days
    Show answer

    Answer: D. 120 days

    The spleen removes aged cells.

15. Red blood cells lack a nucleus, which:

    1. A. Lets them divide in the bloodstream
    2. B. Makes them larger and stiffer
    3. C. Gives them a longer lifespan
    4. D. Leaves more room for hemoglobin
    Show answer

    Answer: D. Leaves more room for hemoglobin

    It also means they cannot divide or repair. Without a nucleus they cannot make new proteins, which helps limit their life to about 120 days.

16. Hemoglobin consists of:

    1. A. Lipid and protein layers
    2. B. Globin chains without iron
    3. C. Albumin bound to iron
    4. D. Globin and iron-rich heme
    Show answer

    Answer: D. Globin and iron-rich heme

    Each molecule carries up to four oxygen molecules.

17. Anemia is best defined as:

    1. A. Reduced total circulating volume
    2. B. A low platelet count with bleeding
    3. C. An elevated white cell count
    4. D. Reduced oxygen-carrying capacity
    Show answer

    Answer: D. Reduced oxygen-carrying capacity

    Fatigue, pallor, and tachycardia are typical. It results from fewer red cells or less hemoglobin.

18. Erythropoietin is produced by the:

    1. A. Spleen
    2. B. Bone marrow
    3. C. Kidneys
    4. D. Liver
    Show answer

    Answer: C. Kidneys

    Chronic kidney disease causes anemia for this reason.

19. White blood cells primarily function to:

    1. A. Defend against infection
    2. B. Transport hormones
    3. C. Carry oxygen to tissue
    4. D. Form clots at injury sites
    Show answer

    Answer: A. Defend against infection

    There are several distinct types.

20. Lymphocytes are responsible for:

    1. A. Initiating the clotting cascade
    2. B. Specific (adaptive) immunity
    3. C. Releasing histamine in allergy
    4. D. Nonspecific phagocytosis of bacteria
    Show answer

    Answer: B. Specific (adaptive) immunity

    B cells and T cells are lymphocytes. This includes antibody production and cell-mediated responses.

21. Eosinophils increase in:

    1. A. Inherited bleeding disorders
    2. B. Chronic iron deficiency anemia
    3. C. Allergy and parasitic infection
    4. D. Acute bacterial infection
    Show answer

    Answer: C. Allergy and parasitic infection

    They modulate allergic inflammation.

22. Basophils release:

    1. A. Fibrinogen and thrombin
    2. B. Antibodies and complement
    3. C. Histamine and heparin
    4. D. Erythropoietin
    Show answer

    Answer: C. Histamine and heparin

    Mast cells play a similar role in tissue.

23. Monocytes become which cell in tissue?

    1. A. Lymphocytes
    2. B. Platelets
    3. C. Macrophages
    4. D. Neutrophils
    Show answer

    Answer: C. Macrophages

    Macrophages engulf debris and organisms.

24. Leukocytosis refers to:

    1. A. A low white count
    2. B. An elevated white count
    3. C. A low platelet count
    4. D. A high red cell count
    Show answer

    Answer: B. An elevated white count

    It is a general marker of inflammation. Infection is a common cause.

25. Thrombocytes are also known as:

    1. A. White cells
    2. B. Red cells
    3. C. Plasma proteins
    4. D. Platelets
    Show answer

    Answer: D. Platelets

    They initiate clot formation.

26. The first response to vessel injury is:

    1. A. Migration of white cells to the site
    2. B. Formation of a fibrin mesh
    3. C. Aggregation of red blood cells
    4. D. Vascular spasm and platelet plug
    Show answer

    Answer: D. Vascular spasm and platelet plug

    The coagulation cascade follows.

27. The clotting cascade ends with:

    1. A. Platelet plug aggregation
    2. B. Reflex vasoconstriction
    3. C. Fibrinogen converted to fibrin
    4. D. Thrombin converted to prothrombin
    Show answer

    Answer: C. Fibrinogen converted to fibrin

    Thrombin catalyzes that conversion. The result is a stable clot.

28. Vitamin K is important because it:

    1. A. Helps hemoglobin carry oxygen
    2. B. Is needed to make clotting factors
    3. C. Stimulates red cell production
    4. D. Buffers acid in the blood
    Show answer

    Answer: B. Is needed to make clotting factors

    Warfarin interferes with it.

29. Fibrinolysis refers to:

    1. A. Clot formation
    2. B. Platelet production
    3. C. Red cell production
    4. D. Breakdown of a clot
    Show answer

    Answer: D. Breakdown of a clot

    Tranexamic acid inhibits it. It occurs once healing is underway.

30. Plasma proteins include:

    1. A. Albumin and hemoglobin
    2. B. Insulin and glucagon only
    3. C. Albumin, globulins, fibrinogen
    4. D. Hemoglobin and myoglobin
    Show answer

    Answer: C. Albumin, globulins, fibrinogen

    Each has distinct functions.

31. Globulins function largely in:

    1. A. Oxygen transport in red cells
    2. B. Clot formation only
    3. C. Maintaining oncotic pressure
    4. D. Immunity and transport
    Show answer

    Answer: D. Immunity and transport

    Antibodies are gamma globulins. Albumin, not globulin, provides most oncotic pressure.

32. Blood type is determined by:

    1. A. White cell surface markers
    2. B. Plasma protein levels
    3. C. Red cell surface antigens
    4. D. The hemoglobin variant
    Show answer

    Answer: C. Red cell surface antigens

    The ABO and Rh systems matter most.

33. A person with type A blood has:

    1. A. B antigens and anti-A antibodies
    2. B. A antigens and anti-A antibodies
    3. C. A antigens and anti-B antibodies
    4. D. No antigens and two antibodies
    Show answer

    Answer: C. A antigens and anti-B antibodies

    Mismatched transfusion causes hemolysis.

34. Type AB blood is called the universal recipient because it has:

    1. A. A antigens and anti-B antibodies
    2. B. No antigens, with both anti-A and anti-B
    3. C. No antigens and no antibodies
    4. D. A and B antigens, no anti-A or anti-B
    Show answer

    Answer: D. A and B antigens, no anti-A or anti-B

    Type AB red cells carry both A and B antigens, and the plasma has neither anti-A nor anti-B antibodies, so donor red cells of any ABO type are not attacked. A antigens with anti-B antibodies describes type A, no antigens with both anti-A and anti-B describes type O, and no ABO type lacks both antigens and antibodies. Type O negative is the universal donor.

35. Rh factor is significant in pregnancy because:

    1. A. Rh-negative mothers can form anti-Rh antibodies
    2. B. It changes the mother's ABO blood type
    3. C. An Rh-positive mother attacks an Rh-negative fetus
    4. D. It causes severe anemia in the mother
    Show answer

    Answer: A. Rh-negative mothers can form anti-Rh antibodies

    Rh immune globulin prevents sensitization. The danger is to an Rh-positive fetus.

36. A transfusion reaction may present with:

    1. A. Bradycardia with no other signs
    2. B. Fever, chills, and hypotension
    3. C. Itching at the IV site only
    4. D. A localized rash only
    Show answer

    Answer: B. Fever, chills, and hypotension

    Stop the transfusion immediately. Back pain and dark urine may also occur.

37. Blood viscosity refers to:

    1. A. Thickness of blood
    2. B. Hemoglobin concentration
    3. C. Total circulating volume
    4. D. Arterial blood pressure
    Show answer

    Answer: A. Thickness of blood

    Polycythemia raises it. Thickness affects resistance to flow.

38. Serum differs from plasma because serum:

    1. A. Is plasma minus clotting factors
    2. B. Is plasma plus red cells
    3. C. Has more fibrinogen than plasma
    4. D. Still contains platelets
    Show answer

    Answer: A. Is plasma minus clotting factors

    It is what remains after blood clots.

39. Hemolysis refers to:

    1. A. Formation of a fibrin clot
    2. B. Production of white cells
    3. C. Rupture of red blood cells
    4. D. Clumping of platelets
    Show answer

    Answer: C. Rupture of red blood cells

    It releases hemoglobin and potassium.

40. Sickle cell disease causes problems because:

    1. A. White cells crowd the marrow
    2. B. Sickled cells block small vessels
    3. C. Platelets are destroyed early
    4. D. Hemoglobin binds oxygen too tightly
    Show answer

    Answer: B. Sickled cells block small vessels

    Crises cause severe pain and organ damage. Sickled cells are also destroyed early. Hemoglobin S does not hold oxygen too tightly; the problem is that it polymerizes when deoxygenated and distorts the cell.

41. Leukemia is characterized by:

    1. A. Too few white cells produced
    2. B. Uncontrolled abnormal white cells
    3. C. Overproduction of red cells
    4. D. Isolated low platelet count
    Show answer

    Answer: B. Uncontrolled abnormal white cells

    Normal marrow function is crowded out.

42. Hemophilia results from:

    1. A. Lack of vitamin K in the diet
    2. B. Destruction of platelets
    3. C. Deficiency of a clotting factor
    4. D. Excessive clot formation
    Show answer

    Answer: C. Deficiency of a clotting factor

    Minor trauma may cause serious bleeding.

43. Thrombocytopenia refers to:

    1. A. High white cell count
    2. B. Low platelet count
    3. C. Low red cell count
    4. D. High platelet count
    Show answer

    Answer: B. Low platelet count

    Bruising and petechiae may be seen. Bleeding risk increases.

44. A thrombus is:

    1. A. A single activated platelet
    2. B. A plug of fat in a vessel
    3. C. A clot fixed where it formed
    4. D. A clot that travels downstream
    Show answer

    Answer: C. A clot fixed where it formed

    An embolus is a clot that travels.

45. Normal adult hemoglobin is approximately:

    1. A. 20 to 25 g/dL
    2. B. 5 to 8 g/dL
    3. C. 2 to 4 g/dL
    4. D. 12 to 16 g/dL
    Show answer

    Answer: D. 12 to 16 g/dL

    Values differ slightly by sex and reference.

46. Total blood volume in an average adult is approximately:

    1. A. 8 to 10 L
    2. B. 5 to 6 L
    3. C. 1 to 2 L
    4. D. 2 to 3 L
    Show answer

    Answer: B. 5 to 6 L

    Roughly 70 mL/kg.

47. Blood contributes to temperature regulation by:

    1. A. Directly cooling the core organs
    2. B. Producing heat in plasma
    3. C. Carrying core heat to the skin
    4. D. Insulating deep tissue
    Show answer

    Answer: C. Carrying core heat to the skin

    Vasodilation increases that heat loss.

48. Blood helps regulate pH through:

    1. A. Bicarbonate and protein buffers
    2. B. Plasma glucose acting as a buffer
    3. C. Hemoglobin oxygen binding only
    4. D. Sodium and potassium exchange
    Show answer

    Answer: A. Bicarbonate and protein buffers

    The lungs and kidneys complete the system. Glucose is a fuel, not a buffer; it does not bind or release hydrogen ions.

49. The spleen's role in the blood system includes:

    1. A. Filtering and removing old red cells
    2. B. Synthesizing hemoglobin for red cells
    3. C. Producing all platelets in adults
    4. D. Producing most clotting factors
    Show answer

    Answer: A. Filtering and removing old red cells

    It is highly vascular and bleeds heavily when injured. It also stores blood.

50. Carbon dioxide is carried in blood primarily as:

    1. A. Carbonic acid only
    2. B. Bicarbonate ion
    3. C. Dissolved gas
    4. D. Carbaminohemoglobin only
    Show answer

    Answer: B. Bicarbonate ion

    About 70 percent travels as bicarbonate.

51. A shift of the oxyhemoglobin curve to the left means hemoglobin:

    1. A. Has a lower oxygen saturation
    2. B. Holds oxygen more tightly
    3. C. Binds carbon dioxide instead
    4. D. Releases oxygen more easily
    Show answer

    Answer: B. Holds oxygen more tightly

    Alkalosis and hypothermia shift it left. At any given PO2, a left-shifted curve gives a higher saturation, not a lower one, but less oxygen is unloaded to tissues.

52. Which condition would shift the oxyhemoglobin curve to the right?

    1. A. Respiratory alkalosis
    2. B. Low CO2 from hyperventilation
    3. C. Fever and acidosis
    4. D. Hypothermia and alkalosis
    Show answer

    Answer: C. Fever and acidosis

    Tissue unloading improves where it is needed.

53. The percentage of hemoglobin binding sites occupied by oxygen is reported as:

    1. A. Hematocrit
    2. B. Hemoglobin level
    3. C. Partial pressure
    4. D. Oxygen saturation
    Show answer

    Answer: D. Oxygen saturation

    Pulse oximetry estimates it noninvasively.

54. Blood doping or polycythemia increases risk of:

    1. A. Bleeding from platelet dilution
    2. B. Anemia from red cell destruction
    3. C. Hypoxia from low hemoglobin
    4. D. Clots from thicker blood
    Show answer

    Answer: D. Clots from thicker blood

    Extra red cells raise blood viscosity, increasing the risk of clots, stroke, and MI. Thicker blood flows less easily.