Sunday 23 December 2012

FIRST MCQ TEST ANSWER - PART III

11. Pick the wrong statement
a.       Hyperemia is due to increased blood flow
b.      Congested tissues are bright red in appearance
c.       Periorbital edema is usually due to renal failure
Hyperemia in a tissue is due to increased active inflow of blood from the arteries. So oxygenated blood accumulates in the tissue and the tissue appears bright red in colour (erythema).

 Congestion is due to decreased outflow of blood from tissue in veins. So more venous blood (deoxygenated blood) accumulates in the tissue. Because the blood is deoxygenated, blood is reddish-BLUE in colour (cyanosis)

So option B is the wrong statement

12. False about red infarcts
a.       Occurs in loose tissues
b.      Occurs in tissues with dual circulation
c.       Occurs with arterial occlusion

First two statements are right. But the third statement is wrong. Arterial occlusion causes white infarcts. Red infarcts are seen in venous occlusion
13. What is a saddle embolus?
a.       Saddle shaped emboli
b.      Emboli in the saddle area of liver
c.       Emboli in bifurcation of pulmonary vein
d.      None of the above

Option D is the correct answer
14. Antiphospholipid antibody syndrome does not show
a.       Recurrent abortions
b.      Repeated thrombosis
c.       Reduced prothrombin time
d.      Pulmonary hypertension

Antiphospholipid antibody syndrome is an autoimmune disorder where antibodies are produced against our own body proteins and phospholipids. This disorder is common in young females and shows recurrent abortions, repeated thrombosis, pulmonary hypertension etc. So options A, B,D are correct.

Prothrombin time (PT) and Partial thromboplastin time (PTT) are tests for coagulation i.e time taken for clot formation.  
Prothrombin time tests the extrinsic pathway of coagulation whereas PTT tests the intrinsic pathway of coagulation.

As i said, these tests basically measure the time taken for clot formation. So by simple logic, u tend to think that in thrombotic disorders like Antiphospholipid antibody syndrome coagulation occurs easily and time taken for clot formation will be less. But that doesnt happen in Antiphospholipid antibody syndrome. Coagulation tests are actually prolonged in this disorder, particularly PTT.
15. Pick the right answer
a.       Postmortem thrombi show lines of zahn
b.      Arterial thrombi progress in retrograde direction
c.       Arterial thrombi show chicken fat appearance
d.      Postmortem thrombi are attached to blood vessel

Differences between antemortem and postmortem thrombi is an important question. So dont forget to read that. If u make a tabular column and read it will be easy.

Among the options here, only B is correct. All thrombi whether arterial or venous progress towards heart.
So venous thrombi spread in a forward direction in the direction of blood flow itself towards the heart.
Arterial thrombi also move towards the heart, that is in a direction opposite to their normal blood flow. (arteries normally take blood away from heart). so arterial thrombi spread is called retrograde spread.

Options A, B and D are wrong.

Antemortem thrombi shows lines of zahn and is attached to blood vessel. These features are not seen in postmortem thrombi. So options A and D are wrong.

Postmortem thrombi shows chicken-fat appearance but not antemortem thrombi. So option C is also wrong

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