All questions of Hemodynamics for PLAB/UKMLA Exam

Understanding White Infarcts
White infarcts, also known as "anemic infarcts," occur primarily in organs with a single blood supply, leading to ischemia and subsequent necrosis. They are characterized by a pale appearance due to a lack of blood flow and hemorrhage.
Organs Typically Affected by White Infarcts
- Kidney:
- The kidney is highly susceptible to white infarcts due to its end-arterial blood supply. When blood flow is obstructed, ischemic necrosis occurs, resulting in pale, well-defined areas of infarction.
- Spleen:
- The spleen, like the kidney, has a single arterial supply. White infarcts can arise from embolic events, leading to localized ischemia and necrosis, manifesting as pale areas.
- Heart:
- In the heart, white infarcts are commonly seen in the context of myocardial ischemia due to blocked coronary arteries. These infarcts present as pale regions of necrosis on the heart muscle.
Why the Liver is the Exception
- Liver:
- The liver has a dual blood supply from both the hepatic artery and the portal vein. This dual supply allows for collateral circulation. Therefore, when one blood supply is compromised, the liver can often maintain viability through the other source. As a result, infarcts in the liver are usually hemorrhagic (red infarcts) rather than white.
Conclusion
In summary, while white infarcts can occur in the kidney, spleen, and heart due to their vascular anatomy, the liver’s unique dual blood supply protects it from developing white infarcts, making option 'A' the correct answer.