1. Abnormal Cellular Accumulations Flashcards
Where do abnormal cellular accumulations come from?
If a cell can’t metabolise something, it will remain within the cell. Products can derive from:
- cell’s own metabolism
- extracellular space (e.g. Spilled blood)
- outer environment (e.g. Dust)
What are the 5 main groups of intracellular accumulations?
- Water and electrolytes
- Lipids (triglycerides and cholesterol)
- Carbohydrates
- Proteins
- Pigments
What is hydropic swelling and why does it occur?
- Accumulation of fluid in cells.
- Occurs when energy supplies are cut off (eg hypoxia) - Na+ and water influx.
- Indicates severe cellular distress.
Where is hydropic swelling a particular problem, and why?
Brain (cerebral oedema) as swelling presses it against skull and compromises blood supply.
What is steatosis, where and why does this occur?
- Accumulation of triglycerides (lipids).
- Often seen in liver (major organ of fat metabolism).
- Causes:
1. Alcohol (reversible in ~10 days)
2. Diabetes mellitus
3. Obesity
4. Toxins (e.g. Carbon tetrachloride)
Why would cholesterol accumulate in cells and where does it often accumulate?
- Cannot be broken down and is insoluble - can only be eliminated through the liver (so accumulated if liver is compromised). Excess stored in cellular vesicles.
- Accumulates in smooth muscle cells and macrophages in atherosclerotic plaques = foam cells.
What are xanthomas?
Hereditary hyperlipidaemias - accumulation of cholesterol in macrophages of skin and tendons.
What are Mallory’s hyaline and when do these occur?
- Damaged keratin filaments.
- Alcoholic liver disease.
What is alpha1-antitrypsin deficiency?
- Liver produces incorrectly folded alpha1-antitrypsin protein.
- Cannot be packaged by ER - accumulates and is not secreted. Causes liver fibrosis and cirrhosis.
- Systemic deficiency: proteases in lung act unchecked resulting in emphysema.
Give an example of the accumulation of exogenous pigments in cells. What are the consequences?
- Air pollutants (carbon/coal dust/soot) inhaled and phagocytosed by alveolar macrophages.
- Causes anthracosis and blackened peribronchial lymph nodes.
- Usually harmless unless in large amounts - fibrosis and emphysema (coal worker’s pneumoconiosis)
- Tattooing: pigments phagocytosed by macrophages in dermis and remain there. Some pigments will reach draining lymph nodes.
Why do bruises form after trauma?
Leakage of blood causes local excess of iron - accumulation of haemosiderin.
What is haemosiderin?
Iron storage molecule derived from haemoglobin (yellow/brown).
What is haemosiderosis? When does this occur?
Deposition of haemosiderin in many organs due to systemic iron overload.
Seen in haemolytic anaemias, blood transfusions and hereditary haemochromatosis.
What is hereditary haemochromatosis?
- Genetically inherited disorder resulting in increased intestinal absorption of dietary iron.
- Iron is deposited in skin, liver, pancreas heart and endocrine organs - often associated with scarring in liver (cirrhosis) and pancreas (can cause pancreatic insufficiency).
What are the symptoms of hereditary haemochromatosis?
Liver damage, heart dysfunction and multiple endocrine failures (esp of pancreas).
‘Bronze diabetes’ as causes tanning and pancreatic destruction.