Reversible vs. Irreversible Cell Injury
1. The Continuum of Injury
Cell injury progresses along a spectrum. The primary determinant of whether a cell can recover is the severity of the insult and the cell’s ability to maintain homeostasis.
2. Comparison Table
| Feature | Reversible Injury | Irreversible Injury |
|---|---|---|
| ATP Levels | Decreased (but present) | Severe depletion |
| Cellular Status | Hydropic swelling | Membrane rupture/Enzymatic digestion |
| Mitochondria | Swelling | Amorphous densities (calcium deposits) |
| Nucleus | Chromatin clumping | Pyknosis → Karyorrhexis → Karyolysis |
3. The “Point of No Return.”
Two phenomena characterize the transition to irreversible injury:
- Inability to reverse mitochondrial dysfunction: Lack of oxidative phosphorylation and ATP generation despite resolution of the insult.
- Profound membrane damage: Loss of integrity of plasma, lysosomal, and mitochondrial membranes, leading to leakage of cellular enzymes (e.g., Troponin, LDH, AST/ALT) into the extracellular space.
4. Note on Free Educational Resources
For high-quality practice questions and in-depth reviews of these cellular pathology mechanisms, visit mymedschool.org to find curated medical course materials and assessment tools.