25 Flashcards
- Normal hemostasis depends on all of the following except
A. an intact vascular system
B. inadequate numbers of platelets
C. appropriate coagulation factors
D. fibrinolysis
B. inadequate numbers of platelets
The sequence of events following injury to a small blood vessel is (2) ______ to (3) ______ to (4) ______ to (5) ______ to (6) ______.
A. contact between damaged blood vessel, blood platelets, and coagulation proteins
B. formation of a platelet plug
C. fibrinolysis and reestablishment of vascular integrity
D. development of a blood clot around the injury
E. blood vessel spasm (vasoconstriction)
- E. blood vessel spasm (vasoconstriction)
- B. formation of a platelet plug
- A. contact between damaged blood vessel, blood platelets, and coagulation proteins
- D. development of a blood clot around the injury
- C. fibrinolysis and reestablishment of vascular integrity
- Which blood vessels have the thickest walls?
A. Veins
B. Arteries
C. Capillaries
D. Arterioles
B. Arteries
- All blood and lymphatic vessels are lined with
A. endothelium
B. nerve endings
C. stratified epithelial cells
D. simple squamous epithelium
A. endothelium
- Blood passes from the arterial to the venous system via
A. arterioles
B. capillaries
C. veins
D. arteries
B. capillaries
The initiating stimulus to blood coagulation following injury to a blood vessel is
A. contact activation with collagen
B. vasoconstriction
C. stenosis
D. release of serotonin
A. contact activation with collagen
Endothelium is involved in the metabolism and clearance of molecules such as
A. serotonin
B. angiotensin
C. bradykinin
D. all of the above
D. all of the above
Which of the following is not correct?
A. Vasoconstriction reduces blood flow and promotes contact activation of platelets and coagulation factors.
B. Platelets adhere to exposed endothelial connective tissues.
C. Aggregation of platelets releases thromboxane A2 and vasoactive amines (serotonin and epinephrine).
D. None of the above.
D. None of the above.
Which of the following is (are) true of endoreduplication?
A. Duplicates DNA without cell division
B. Results in cells with ploidy values of 4n, 8n, 16n, and 32n
C. Is unique to the megakaryocytic type of blood cell
D. All of the above
D. All of the above
Which of the following is (are) true of thrombopoietin?
A. Thought to stimulate the production and maturation of megakaryocytes
B. Is influenced by various cytokines, which increase megakaryocyte size
C. Is influenced by various cytokines, which impact maturational stage and ploidy
D. All of the above
D. All of the above
Which of the following is not a characteristic of platelets?
A. The presence of a nucleus
B. Life span of 9 to 12 days.
C. Cytoplasm is light blue with fine red-purple granules.
D. A discoid shape as an inactive cell.
A. The presence of a nucleus
The cellular ultrastructural component unique to the platelet is the
A. cytoplasmic membrane
B. glycocalyx
C. mitochondrion
D. microtubule
B. glycocalyx
Choose the incorrect statement regarding storage granules related to hemostasis in the mature platelet.
A. Alpha-granules contain platelet factor 4, beta-thromboglobulin, and platelet-derived growth factor.
B. Alpha-granules contain platelet fibrinogen and von Willebrand factor.
C. Dense bodies contain serotonin and ADP.
D. Lysosomes contain actomyosin, myosin, and filamin.
D. Lysosomes contain actomyosin, myosin, and filamin.
- At all times, approximately ______ of the total number of platelets are in the systemic circulation.
A. one fourth
B. one third
C. one half
D. two thirds
D. two thirds
- The reference range of platelets in the systemic circulation is
A. 50 to 150 × 10^9/L
B. 100 to 200 × 10^9/L
C. 150 to 350 × 10^9/L
D. 150 to 400 × 10^9/L
D. 150 to 400 × 10^9/L
- The functions of platelets in response to vascular damage include
A. maintenance of vascular integrity by sealing minor defects of the endothelium
B. formation of a platelet plug
C. promotion of fibrinolysis
D. all of the above
B. formation of a platelet plug
- If vascular injury exposes the endothelial surface and underlying collagen, platelets (21A) ______ to the collagen fibers and (21B) ______.
A. adhere
B. aggregate
C. do not adhere
D. both a and b
A. adhere
- The end production of _________ occurs with platelet aggregation.
A. thromboxane A2
B. cyclooxygenase
C. prostacyclin
D. arachidonic acid
B. cyclooxygenase
Agents that are capable of aggregating platelets include
A. collagen
B. thrombin
C. serotonin
D. all of the above
D. all of the above
- Examination of a Wright-stained peripheral blood smear provides an estimate of platelet numbers. Using 100× (oil) immersion in the areas of erythrocytes just touching each other, the upper limit of the number of platelets seen per field should not exceed
A. 10
B. 15
C. 20
D. 25
C. 20
- If 10 platelets are seen per oil immersion field, what is the approximate platelet count?
A. 50 × 10^9/L
B. 100 × 10^9/L
C. 150 × 10^9/L
D. 200 × 10^9/L
D. 200 × 10^9/L
- Aspirin ingestion has the following hemostatic effect in a normal person:
A. Prolongs the bleeding time
B. Prolongs the clotting time
C. Inhibits factor VIII
D. Has no effect
A. Prolongs the bleeding time
- The bleeding time test measures
A. the ability of platelets to stick together
B. platelet adhesion and aggregation on locally injured vascular subendothelium
C. the quantity and quality of platelets
D. antibodies against platelets
B. platelet adhesion and aggregation on locally injured vascular subendothelium
- The clot retraction test is
A. a visible reaction to the activation of platelet actomyosin (thrombosthenin)
B. a reflection of the quantity and quality of platelets and other factors
C. a measurement of the ability of platelets to stick to glass
D. a measurement of the cloudiness of blood
B. a reflection of the quantity and quality of platelets and other factors
