Which finding on electron microscopy indicates irreversible cell injury?
**Core Concept**
Cell injury can be reversible or irreversible. Reversible cell injury is characterized by cellular dysfunction without significant ultrastructural changes, whereas irreversible cell injury leads to cell death and distinct changes visible on electron microscopy.
**Why the Correct Answer is Right**
Irreversible cell injury is marked by the loss of cell membrane integrity and the appearance of blebs or vesicles on the cell surface. The underlying mechanism involves the breakdown of the cytoskeleton and the disruption of the plasma membrane, leading to the loss of cellular contents and the activation of cellular enzymes that contribute to cell death. This process is often initiated by severe cellular stress, such as ischemia or toxin exposure.
**Why Each Wrong Option is Incorrect**
**Option A:** Swelling of mitochondria is a common finding in reversible cell injury, as it reflects the accumulation of calcium ions and the disruption of mitochondrial function. However, it does not necessarily indicate irreversible cell injury.
**Option B:** The presence of myelin figures is a characteristic finding in reversible cell injury, reflecting the disruption of cell membrane structure and function. However, it is not a definitive indicator of irreversible cell injury.
**Option C:** The appearance of a "basket weave" pattern on electron microscopy is associated with viral infections and represents the aggregation of intracellular viral particles. It is not a specific indicator of irreversible cell injury.
**Clinical Pearl / High-Yield Fact**
In electron microscopy, the presence of blebs or vesicles on the cell surface is a critical indicator of irreversible cell injury. This finding is often accompanied by the loss of cell membrane integrity and the appearance of cellular debris.
**Correct Answer:** C.