Cellular injury can manifest through several observable features: • Cellular Swelling: This is often an early sign of injury. The cell membrane's ability to regulate ion and fluid concentrations is impaired, leading to an influx of water and swelling of organelles like the endoplasmic reticulum and mitochondria. • Fatty Change: This occurs primarily in cells that metabolize fats, such as liver and kidney cells. Injury can disrupt normal fat metabolism, leading to the accumulation of fat vacuoles within the cytoplasm. • Plasma Membrane Damage: Injury can compromise the integrity of the plasma membrane. This can lead to the leakage of cellular contents, such as enzymes (e.g., troponins, creatine kinase) into the bloodstream, which can be detected in diagnostic tests. • Mitochondrial Swelling and Dysfunction: Mitochondria are sensitive to injury. They may swell, and their function in ATP production can be impaired, leading to energy depletion. • Endoplasmic Reticulum (ER) Dilatation: The ER can dilate, and ribosomes may detach from its surface, impairing protein synthesis. • Nuclear Alterations: The nucleus can undergo changes such as pyknosis (condensation and darkening of chromatin), karyorrhexis (fragmentation of the nucleus), or karyolysis (dissolution of the nucleus).