Pathology - Reversible Cell Injury Flashcards
What type of cell injury is considered “reversible”?
Cell injury that is mild and transient can be reversible if the stimulus is removed.
What is the first stage of “irreversible” cell injury?
Biochemical alterations are the first stage to occur. These changes may not be seen with the naked eye, but may have signs (ex. fluid).
What is the second stage of “irreversible” cell injury?
Ultrastructural changes are the second stage of irreversible cell injury. These changes cannot be seen with the naked eye, but can be seen with Electron Microscopy.
What is the third stage of “irreversible” cell injury?
Light microscopic changes are the third stage and these changes can be seen under normal light microscopy.
What is the final stage of “irreversible” cell injury?
Gross morphological changes are the final stage of irreversible cell injury and these changes are the most severs and can be seen with the naked eye.
What are the morphological correlates of “reversible” cell injury?
Cellular swelling and Fatty changes (lipidosis)
What are the morphological correlates of “irreversible” cell injury?
Necrosis, Apoptosis and other types of cell death.
Define the term “Acute Cell Swelling” and give other terms that mean the same thing.
Acute cell swelling is an early, sub-lethal manifestation of cell injury caused by an increase in the size and volume due to water overload. Organelles like mitochondria and ER become dilated and swollen. It is the most common and fundamental expression of cell injury.
Acute cell swelling can also be called Hydropic degeneration, Hydropic change, Cytotoxic edema (in CNS), or ballooning degeneration (in epidermis).
List some cell types that are highly vulnerable to Hypoxia and Cell Swelling.
- Cardiomyocytes
- Proximal tubule epithelial cells (if you see white stripes there is likely hypoxic change)
- Hepatocytes
- Endothelium (prone to leakage and permeability when there is hypoxic change)
- CNS neurons, oligodendrocytes, astrocytes (cytotoxic edema)
List some cell types that are rarely, if ever, affected by hypoxic change.
- Bone
- Cartilage
- Connective tissue
- Adipose tissue
What are some possible etiologies of acute cell swelling?
Loss of ionic and fluid homeostasis (loss of ionic and fluid transport across the membrane). Possible causes:
- Failure of cell energy production
- Cell membrane damage
- Injury to enzymes regulating ion channels of the membrane.
*Most common examples = Hypoxia and Toxic agents.
What are some gross morphological changes you might see with acute cell swelling?
- Swollen organ with rounded edges
- Pallor than normal
- Slightly heavy (“wet organ”)
Cutaneous vesicles on a pig’s snout is an example of what type of cell injury?
Ballooning degeneration.
Describe the histological appearance of cellular swelling.
Cells are larger with pale, dilute cytoplasm. Nucleus is in the normal position with no morphological change.
Describe the Ultrastructural changes of cellular swelling.
- Plasma membrane changes: blebbing, blunting and loss of microvilli
- Mitochondrial changes: swelling and small amorphous densities
- Dilation of the ER
- Nuclear alterations: dissaggregation of granular and fibrillar elements. Clumping of nuclear chromatin.
What is the difference between Cell Swelling (Hydropic change, Fatty change) and Hypertrophy (Cell enlargement)?
Cell swelling is due to an increase in the uptake of water, which diffuses to organelles and cytoplasmic proteins.
Hypertrophy is cell enlargement due to an increase in size of normal organelles.
In both, the cell is larger, but the mechanisms and pathogenesis are different.
What is the significance of Lipofuscin in a cell?
This is the wear and tear pigment, and it is evidence of previous injury.
Define the term Fatty change (Lipidosis).
It is a sub-lethal cell damage caused by intracytoplasmic fatty vacuolation, which may be proceeded or accompanied by cell swelling.
What are the major classes of lipids that commonly accumulate in the cells with Fatty change?
- Triglycerides (esp in Liver)
- Cholesterol
- Phospholipids
- Abnormal complexes of lipids and carbohydrates
What is the mechanism leading to elevated liver enzymes and icterus in Hepatic Lipidosis?
Hepatocytes packed with lipids can compress adjacent structures and result in alteration of liver profile on biochemistry. Can also compress the bile ducts, so bile pigment will be retained and back up into the blood stream, leading to icterus.
What are some of the main causes/etiologies of Fatty change?
Hypoxia, toxicity and metabolic disorders.
Commonly seen in abnormalities of synthesis, utilization and/or mobilization of fat.
A very common cause of hypoxia is anemia, this can lead to fatty change.
Describe the pathogenesis of Fatty Liver (Hepatic Lipidosis).
- Excessive delivery of FFAs from fat stores or from diet (often occurs in sudden starvation)
- Decreased oxidation or use of FFAs
- Impaired synthesis of apoprotein
- Impaired combination of protein and triglycerides to form lipoproteins
- Impaired release of lipoproteins from hepatocytes.
Describe the gross morphological changes you might see in Fatty Liver.
- Liver will be a diffuse yellow in color.
- Edges will be round and bulge on section
- Tissue will be soft, friable and greasy
- If severe, liver sections may float in water or fixative.
What is an example of “physiologic” Hepatic lipidosis mentioned in lecture?
- Pregnancy toxemia in later pregnancy
- Ketosis in heavy early lactation in ruminants.
