Summary Pathology: Cell injury, Cell death and Cellular Adaptation.

PATHOLOGY

Cell Injury, Cell Death, and Cellular Adaptation*

Cell Injury
It’s the cellular esponse to stress, leading to reversible or irreversible changes

Causes
- Hypoxia (most common)
- Toxins (chemical, drugs)
- Infections (bacterial, viral)
- Genetic factors (mutations)
- Immunologic reactions (hypersensitivity)
- Nutritional imbalances

Mechanisms
- ATP depletion → cellular swelling
- Mitochondrial damage → apoptosis/necrosis
- Membrane damage → influx of Ca²⁺, cell lysi

Morphologic Changes
- Cellular swelling (hydropic change)
- Fatty change (steatosis)
- Membrane blebbing

Cell Death
Necrosis
- Its the pathologic cell death due to injury

Types
- *Coagulative necrosis*: ischemic injury (e.g., MI)
- *Liquefactive necrosis*: enzymatic digestion (e.g., brain infarct)
- *Caseous necrosis*: TB, granulomas
- *Fat necrosis*: pancreatitis
- *Gangrenous necrosis*: ischemia + infection

Features
Cell swelling
Membrane rupture
Inflammation

Apoptosis
It’s the programmed cell death

Features
Cell shrinkage,
Nuclear fragmentation,
Apoptosis bodies