Cardiac Pathology Flashcards

1
Q

What is oedema? Explain how it is caused.

A

Oedema is an accumulation of fluid in the interstitial space. It can be caused by: (1) alterations in Starling’s forces - either an increase in the capillary hydrostatic pressure or a decrease in the plasma oncotic pressure; (2) an obstruction to lymphatic drainage or (3) an increase in vascular permeability.

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2
Q

What are hyperaemia and congestion?

A

In both hyperaemia and congestion, there is an increased amount of blood in the vessels of an organ/tissue. In hyperaemia, this is an active process = it is accompanied by an increase in blood flow. In congestion, I this is a passive process = it is caused by an obstruction to the outflow of blood.

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3
Q

What is Virchow’s Triad?

A

Virchow’s triad explains the 3 major abnormalities that cause thrombosis. These are: (1) endothelial injury; (2) hypercoagulability of the blood; (3) abnormal blood flow - either stasis or turbulence.

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4
Q

What are the macroscopic and microscopic features of a thrombus?

A

Macroscopic: there is solid or semi-solid material present in the vessel lumen; material is red-brown and friable; it extends along the vessel in the direction of blood flow.
Microscopic features: platelet aggregation with the deposition of fibrin (platelets are dominant in arteries and fibrin is dominant in veins); there may be alternating layers called ‘lines of Zahn’.

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5
Q

What are the 4 fates of a thrombus?

A

(1) Propagation –> with progressive occlusion of the vessel.
(2) Detachment –> with embolization.
(3) Dissolution –> by the action of fibrinolytic enzymes.
(4) Organisation and recanalization –> new channels form through the thrombus.

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6
Q

What is an embolus?

A

An embolus is a detached intravascular solid, liquid or gaseous mass that is carried by the blood from its point of origin to a distant site.

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