Chapter 14: Alterations in Hemostasis and Blood Coagulation

Chapter 14: Alterations in Hemostasis and Blood Coagulation

Complete Chapter Questions With Answers

Sample Questions Are Posted Below

MULTIPLE CHOICE
1. A normal bleeding time in association with normal platelet count, and increased prothrombin time (PT) and INR, is indicative of
a. vitamin K deficiency.
b. hemophilia B.
c. hemophilia A.
d. idiopathic thrombocytopenia.
ANS: A
Vitamin K deficiency should be considered as the cause for bleeding when the PT and INR are increased but other coagulation
studies are normal. Hemophilia B results from factor deficiency or the abnormal function of factor IX. Hemophilia A results from
factor deficiency or the abnormal function of factor VIII. In idiopathic thrombocytopenia, a decreased platelet count isseen in
prolonged bleeding times.
REF: Pg. 306
2. The final step in clot formation is
a. conversion of prothrombin to thrombin.
b. platelet degranulation and adhesion.
c. conversion of fibrinogen to fibrin.
d. clot retraction.
ANS: D
Clot retraction, the final stage of clot formation, occurs when the components of the fibrin clot are compressed or contracted to form
a firm clot. Platelets serve as a catalyst in accelerating the conversion of prothrombin to thrombin. Platelet degranulation is not
involved in clot formation. The formation of a fibrin clot occurs when fibrinogen is converted to fibrin, usually at the site of an
injury.
REF: Pg. 295
3. Dysfunction of which organ would lead to clotting factor deficiency?
a. Liver
b. Kidney
c. Spleen
d. Pancreas
ANS: A
The liver is responsible for the synthesis of coagulation factors. A clotting factor deficiency is the result of liver dysfunction.
Coagulation does not occur in the kidneys. About 25% of the total number of platelets can be found in the spleen. The pancreas is
not a location where coagulation occurs.
REF: Pg. 295
4. The conversion of plasminogen to plasmin results in
a. clot retraction.
b. fibrinolysis.
c. platelet aggregation.
d. activation of thrombin.
ANS: B
Fibrinolysis is the process of clot dissolution and occurs when plasminogen activators cleave plasminogen to plasmin. Clot
retraction occurs when the components of the fibrin clot are compressed or contracted to form a clot. Factors released from platelets
contribute to hemostasis by enhancing vasoconstriction, platelet aggregation, and vessel repair. Platelet aggregation is not the result
of plasmin conversion. Thrombin cleaves fibrinogen to form a fibrin clot.
REF: Pg. 297 | Pg. 299
5. Activation of the extrinsic pathway of coagulation is initiated by
a. platelet factors.
b. collagen exposure.
c. tissue thromboplastin.
d. factor VII.
ANS: C
The extrinsic pathway of coagulation begins when the vascular wall is traumatized. Tissue factor from injured tissue activates
factors which in turn activate and convert into thrombin for clotting. Platelets play a major role in primary hemostasis as well as
secondary hemostasis and clot retraction. Platelets accelerate the conversion of prothrombin to thrombin. Platelets adhere to
collagen exposed by trauma and initiate degranulation. Factor VII is involved in the extrinsic pathway of coagulation when it is
activated by tissue factor following a traumatic injury.