Hemodynamics Flashcards
All are true about blood coagulation except
A. Factor X is a part of both intrinsic and extrinsic pathway
B. Extrinsic Pathway is activated by contact of plasma with negatively charged surfaces
C. Calcium is very important for coagulation
D. Intrinsic pathway can be activated invitro
Answer - B. Extrinsic Pathway is activated by contact of plasma with negatively charged surfaces
Vitamin K is responsible for carboxylation of which amino acid in the clotting factors? A. Aspartate B. Glutamate C. Proline D. Lysine
Answer -B. Glutamate
The binding of clotting factors II, VII, IX and X depends on the addition of gamma carboxylation of glutamate on these proteins. This step requires vitamin K as cofactors.
Protein C and protein S are two other vitaminK dependent proteins that inactivate factors Va and VIIIa. These are anticlotting factors.
Initiating mechanism in endotoxic shock is A. Peripheral vasodilation B. Endothelial injury C. Increased vascular permeability D. Reduced cardiac output
Answer - B. Endothelial injury
The initiating mechanism is endothelial activation and injury, whereas the options are sequelae following it, eg reduced cardiac output, increase in vascular permeability and vasodilation
Edema in nephrotic syndrome occurs due to A. Na and water retention B. Increased venous pressure C. Decreased Serum albumin D. Decreased fibrinogen
Answer- C. Decreased serum albumin
Heavy proteinuria depletes serum albumin at a rate beyond compensatory synthetic activity of the liver resulting in reversed A:G ratio. The generalized edema of nephrotic syndrome in turn a consequence of drop in plasma colloid osmotic pressure with subsequent accumulation of fluid in interstitial tissues. There is also sodium and water retention by the kidney which aggravates the edema.
But hypoproteinemia is the primary cause of edema whereas sodium and water retention aggravates the edema.
Pale infarct is seen in all except A. Lungs B. Spleen C. Kidney D. Heart
Answer - A. Lungs
In organs like lungs and small intestine, red infarcts are seen. Whereas in solid organs like heart, spleen and kidney white or pale infarcts can be seen.
Congenital hypercoagulability states all except A. Protein C deficiency B. Protein S deficiency C. Anti-phospholipid antibody syndrome D. MTHFR gene mutation
Answer- C. Antiphospholipid antibody syndrome.
Thrombomodulin thrombin complex prevents clotting because
A. Thrombomodulin inhibits prothrombin activator
B. The complex activates antithrombin III
C. Thrombomodulin- thrombin complex activates heparin
D. The complex removes thrombin and also activates protein C which inactivates the activated factors V and VIII
Answer - D. The complex removes thrombin and also activates protein C which inactivates the activated factors V and VIII
Fat embolism is commonly seen in A. Head injuries B. Long bone fractures C. Drowning D. Hanging
Answer- B. Long bone fractures
D-dimer is the most sensitive diagnostic test for A. Pulmonary embolism B. Acute pulmonary edema C. Cardiac tamponade D. Acute myocardial infarction
Answer - A. Pulmonary embolism
D-dimer is a fibrin degradation product, a small protein fragment present in the blood after blood clot is degraded by fibrinolysis. It is so named because it contains 2 cross linked D fragments of fibrinogen protein. D dimer concentration may be determined by a blood test to help diagnose thrombosis. D-dimer testing is of clinical use when there is suspicion of DVT or pulmonary embolism. In patents suspected of disseminated intravascular coagulation, D-dimers may aid in diagnosis.
Vitamin K associated clotting factors are - A. IX, X B. I, V C. VII, VIII D. I, VIII
Answer - A. IX, X
All endothelial cells produce thrombomodulin except those found in A. Hepatic circulation B. Cutaneous circulation C. Cerebral microcirculation D. Renal circulation
Answer- C. Cerebral microcirculation
All endothelial cells except those in the Cerebral microcirculation produce thrombomodulin, a thrombin protein and express it on their surface.
Endothelial cells produce anti-thrombotic effects by the following mechanisms -
1)Antiplatelet effects - PGI2, NO, Ecto ADPase/CD39
2)Anticoagulant effects - Heparan proteoglycans, Antithrombin, tissue factor pathway inhibitor, thrombomodulin
3) Fibrinolytic activators - tissue plasminogen activator -1, urokinase, annexin-2
Which of the following is a procoagulation protein A. Thrombomodulin B. Protein C C. Protein S D. Thrombin
Answer - D. Thrombin
Thrombin is a clotting factor IIa which participates in coagulation cascade by converting factor I (soluble protein fibrinogen) to factor Ia (insoluble fibrin)
Protein C and protein S are vitamin K dependent anticlotting proteins these act by inactivating factor Va and VIIIa. (remember factor II, VII, IX and X are vitamin K dependent clotting factors)
Thrombomodulin-thrombin complex activates protein C and thus the complex acts as anticoagulant.
All of the following are correct about thromboxane A2 except
A. Low dose aspirin inhibits its synthesis
B. Causes vasoconstriction in blood vessels
C. Causes bronchoconstriction
D. Secreted by WBC
Answer - D. Secreted by WBC
Thromboxane A2 is synthesized and released from activated platelets (not WBC)
TXA2 is a powerful vasoconstrictor and bronchoconstrictor.
Low dose Aspririn is used as anti platelet drug because it inhibits COX irreversibly and decreases formation of TXA2 by platelets.
Virchow's triad includes all except A. Injury to vein B. Venous thrombosis C. Venous stasis D. Hypercoagulability of blood
Answer - B. Venous thrombosis
Virchow’s triad inculdes -
- Stasis
- Vascular damage
- Hypercoagulability
Shock lung is characterised by A. Alveolar proteinosis B. Bronchiolitis obliterans C. Diffuse pulmonary hemorrhage D. Diffuse alveolar damage
Answer - D. Diffuse alveolar damage
Shock lung is also known as acute respiratory distress syndrome, diffuse alveolar damage, acute alveolar injury and acute lung injury.
