Time taken by tissue to develop frank necrosis is around:
**Core Concept**
The question tests understanding of **ischemic injury** and its effects on tissue, specifically the time frame for the development of **frank necrosis**. Ischemia leads to a lack of oxygen and nutrients, causing cellular damage.
**Why the Correct Answer is Right**
Frank necrosis typically occurs after a significant period of ischemia, during which cellular energy sources are depleted, and **anaerobic metabolism** cannot sustain cellular functions. The exact time can vary depending on the tissue type, but generally, it's around 20-30 minutes for neuronal tissue and can be longer for other tissues.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is too short, as it doesn't account for the time needed for significant cellular damage to occur.
**Option B:** While close, the precise timing can vary, but this option might not accurately represent the average time for most tissues.
**Option C:** This option might be too long for sensitive tissues like neurons.
**Option D:** This is not a commonly cited time frame for the onset of frank necrosis in the context of ischemia.
**Clinical Pearl / High-Yield Fact**
Remember, the time to necrosis can vary significantly between different tissue types, with the brain being one of the most sensitive to ischemia.
**Correct Answer:** D. 20 minutes