Blood and Clotting

What type of blood cell grows from a lymphoid precursor cell? A. Erythrocyte B. Megakaryocyte C. Natural killer cell D. Neutrophil

C. Natural killer cell The natural killer cell (NK cell) grows from lymphoid precursor cells. Erythrocytes, megakaryocytes, and neutrophils all come from myeloid precursor cells.

In an emergency situation, blood from a universal donor can be given. What blood type is reflected in a "universal donor" status? A. AB-negative B. AB-positive C. O-negative D. O-positive

C. O-negative Individuals who have O-negative blood are universal donors. O-positive and AB-negative blood donors are not universal donors. AB-positive blood has all AB and Rhesus-factor identifying proteins on their surface, making them universal recipients.

What molecule is a naturally occurring anticoagulant? A. Antithrombin B. Fibrinogen C. Proconvertin D. Prothrombin

A. Antithrombin Antithrombin is a serine protease inhibitor that inactivates thrombin, factor IXa, factor Xa, factor Xia, and factor XIIa, all of which are involved in the coagulation cascade. Fibrinogen is essential for coagulation. Proconvertin activates factors IX and X. Prothrombin, a relatively unstable protein, activates factors I, V, VII, VIII, XI, XIII, protein C, and platelets.

What clotting factor specifically involves the common pathway? A. Factor II B. Factor VIII C. Factor IX D. Factor XII

A. Factor II Factor II is prothrombin, which gets converted to thrombin as part of the common pathway. Factor IX, factor VIII, and factor XII are all a part of the intrinsic coagulation pathway.

ABO/Rh classification of blood indicates the different antigens that are possibly present on the red blood cell (RBC) surface. In a scenario where emergency blood or plasma transfusion is necessary, which blood type would be a universal donor of RBCs and which blood type would be a universal donor of plasma, respectively? A. O-, AB+ B. O+, AB+ C. AB+, O- D. AB-, O-

A. O-, AB+ A, B, O, and Rh are antigens present on red blood cells (RBC) in different combinations among individuals depending on their genetic makeup. In a healthy individual, having an antigen on the RBC indicates the body tolerates that type of antigen and will not create an antibody in the plasma against it. On the other hand, if an individual does not have a certain antigen on their RBCs, one can assume the body has generated an antibody previously or will generate an antibody against that missing antigen. Antibodies are present in the plasma component of whole blood. In summary, O- donor blood has no A, B, or Rh antigen on the RBC, so no recipient will react to break it down (hemolysis). AB+ donor plasma will contain no A, B, or Rh antibody, since donor RBC in that plasma has survived in the donor previously.

A 25-year-old healthy Rh-negative woman is pregnant with an estimated gestational age of 3 months (end of the first trimester). An amniocentesis reveals that her fetus is Rh-positive. Her past medical history is significant for a single prior pregnancy, which she remembers was Rh-negative, was carried to term, and was delivered at home. She remembers only that the baby was healthy and can recall no further details. What is most appropriate in the care of this patient? A. Continue routine prenatal care only. B. Continue routine prenatal care, Rh immune globulin after delivery. C. Continue routine prenatal care, Rh immune globulin first trimester of next pregnancy. D. Give the patient a dose of Rh immunoglobulin now. E. Monitor maternal Rh antibody titers, exchange transfusion of the newborn after delivery.

B. Continue routine prenatal care, Rh immune globulin after delivery. When an Rh-negative mother gives birth to an Rh-positive fetus for the first time, she can develop significant titers of anti-Rh antibodies due to exposure to Rh-positive blood. During any subsequent pregnancies with an Rh-positive fetus, these antibodies can cross the maternal-fetal circulation and cause hemolysis, leading to hemolytic disease of the newborn. This can be prevented by giving the mother a dose of Rh-immunoglobulin to prevent sensitization immediately after delivery. It is this patient's first Rh-positive pregnancy, so it is appropriate to continue routine prenatal care and administer a dose of Rh immunoglobulin immediately after she gives birth. In situations where the risk of fetal-maternal hemorrhage is high, such as blunt trauma or placental rupture, the Rh-immunoglobulin is recommended immediately. Giving routine prenatal care only or giving the Rh-immunoglobulin during her next pregnancy is not appropriate because that does not address her current risk of Rh-sensitization. Monitoring maternal Rh titers and exchange transfusion are treatments for hemolytic disease of the newborn. This is appropriate if this were not her first Rh-positive pregnancy; her current Rh-positive fetus is not at risk.

What is the main role of neutrophils in the blood? A. Deliver carbon dioxide to the lungs B. Destroy bacteria through phagocytosis C. Destroy infected body cells D. Secrete antibodies

B. Destroy bacteria through phagocytosis Blood consists of plasma and formed elements (erythrocytes, leukocytes, and platelets). Neutrophils are regarded as the most abundant phagocytic type of leukocytes. They immediately respond to injury and inflammation. Their course of action is phagocytic, which implies devouring or eating the pathogenic material present. Neutrophils do not secrete antibodies or transport carbon dioxide. Other leukocytic components destroy cells of the infectious material.

What type of leukocyte is activated in parasitic worm infections and is a marker for this type of infection? A. Basophil B. Eosinophil C. Monocyte D. T lymphocyte

B. Eosinophil Eosinophils are markers for parasitic worm infections and are activated in these types of infections. The monocyte can be activated in any infection. T lymphocytes participate in cytotoxic cellular immunity (which mainly fights off viruses and special bacteria). Basophils primarily lead to histamine release, as seen in allergic reactions.

Why is type O negative blood considered a universal donor? A. It can be mixed with other blood types. B. It has no antigens on the outside of the red blood cells. C. It is not charged. D. The red blood cells do not attack other blood types.

B. It has no antigens on the outside of the red blood cells. Type O negative blood is considered a universal donor because it has no antigens on the outside of the red blood cells, so the recipient's immune system will not react to it. It cannot be mixed with other blood types because other blood types that differ from the recipient would elicit an immune response. The negative in the nomenclature represents Rh negative, not a charge. Red blood cells do not initiate an "attack" towards other blood cells; the recipient immune system may react to non-host blood types.

What set of tissues composes human blood? A. Oxygen, red blood cells, and white blood cells B. Plasma, platelets, red blood cells, and white blood cells C. Platelets and red blood cells D. Neutrophils, plasma, and proteins

B. Plasma, platelets, red blood cells, and white blood cells Blood is the major substance responsible for carrying oxygen and needed nutrients to every cell in the body. There are about 5 liters of blood in the body, which is composed of plasma and other formed elements: red blood cells, white blood cells, and platelets. Plasma is the fluid these blood cells are suspended in. It is vital in maintaining the proper functions of the formed elements. Red blood cells (erythrocytes) are the oxygen-carrying components of the blood. White blood cells (leukocytes) are essential in immunity. Platelets (thrombocytes) are key to blood clotting.

Factor XII is exposed to endothelial collagen and becomes Factor XIIA, an activated serine protease. A cascade of clotting factors follows and includes factors XI, IX, and X. Which factor displays the highest concentration throughout this progression? A. IX B. X C. XI D. XII

B. X As the cascade progresses, the concentrations of factors are increased relative to preceding factors. The progression of factors as listed within the intrinsic pathway is XII, XIIA, XI, XIA, IX, IXA, X, XA. Factor X has a higher concentration than factors IX, XI, and XII.

During trauma or injury, the body initiates the repair of the damaged tissue. What cells are responsible for developing a mesh-like clot to prevent further loss of blood? A. Fibroblasts B. Macrophages C. Mast cells D. Platelets

D. Platelets A platelet is one of the major formed elements in the blood. It is disc-shaped and clumps together during the blood clotting process. It creates a hemostatic plug during injuries such as cuts and bruises; it also helps in catalyzing coagulation. A fibroblast is a type of cell responsible for synthesizing important bodily substances like collagen. A mast cell, one of the leukocytes, is rich in histamine and heparin. It has important functions relating to allergy and anaphylaxis. A macrophage is another type of leukocyte usually found in connective tissues and blood. It destroys foreign particles and microorganisms through phagocytosis.

What type of blood type problem most contributes to the development of erythroblastosis fetalis in pregnancy? A. AB/O incompatibility B. A/O incompatibility C. B/O incompatibility D. Rh factor incompatibility

D. Rh factor incompatibility Rh factor incompatibility—the mother is Rh-negative and the fetus is Rh-positive—is the most common cause of erythroblastosis fetalis. There can be situations of A/O incompatibility, B/O incompatibility, and AB/O incompatibility that may lead to this condition, but these are rare.

Hemostasis is the physiological response that stops bleeding at the site of an injury. What is the function of insoluble fibrin? A. Activate thrombin B. Form a platelet plug C. Initiate the coagulation cascade D. Stabilize the blood clot

D. Stabilize the blood clot Insoluble fibrin is a component of secondary hemostasis, which strengthens and stabilizes the blood clot. Formation of the platelet plug during primary hemostasis precedes the deposition of insoluble fibrin. During the coagulation cascade, thrombin is activated, which generates insoluble fibrin.

What clotting molecule is exclusively linked to the extrinsic pathway? A. Anti-hemophilic factor B. Hageman factor C. Prothrombin D. Thromboplastin

D. Thromboplastin Thromboplastin is factor III, which gets activated as part of the extrinsic pathway. Hageman factor and anti-hemophilic factor are part of the intrinsic pathway. Prothrombin (factor II) is part of the common pathway. NEXT