Cellular change in disease are often non-specific or adaptive changes to injury. Cellular disease can be identified if there are:
- External indicators
- Physical measurement changes
- Biochemical changes
- Changes in the pathology of the cell
Cell damage depends on type of agent or stress, type and duration of injury or type of tissue involved.
Cellular changes which are all adaptations to stressors include:
- Hypertrophy
- Atrophy
- Hyperplasia
- Metaplasia
- Dysplasia
Handy Hint! How can you memorize the above?
MADHH (MAD Hairy Head)
Metaplasia, Atrophy, Dysplasia, Hypertrophy, Hyperplasia
How does the lack of oxygen affect cells?
Hypoxia is the lack of oxygen in cells which is the most common cause of cell injury and most commonly caused Ischemia (reduced blood supply) however can also be caused by any of the following:
- Decrease of oxygen in the air
- Loss of haemoglobin or loss of Hb (Haemoglobin) function
- Decrease in RBC (Red Blood Cell) production
- Disease of the respiratory or cardio system
- Poisoned enzymes
Key:
¯ Decreased
↑ Increased
A ¯ in RBC (Red Blood Cell) supply causes a ¯ in Heart Rate, ¯ Contractions ¯ ATP production ↑ anaerobic metabolism, leading to ¯ metabolism when C6H12O6 is depleted, ↑ Na+/K supply, the Na/Ca pump stops, leading to a ↑ Na+ & Ca+ accumulation inside the cell and↑ K+ outside of the cell.
Handy Hint! How can you memorize the above?
Just remember
When there’s not enough of a RBC Supply the cell Kicks K out!
When there is an ↑ in water within the cell, there is an ↑ in swelling which is reversible if the oxygen level ↑
Cell swelling causes cell leakiness which leads to an ↑ in Ca2+ in cells which activate nucleases, which:
- Initiates apoptosis
- Decreases enzyme function
- Lactic Acid
- Releases lysosomal enzymes into the cytoplasm and causes autolysis of cell contents.
A detected ↑ in a type of Enzyme within the cell plasma determines what cell is injured.
If the oxygen level is restored quickly, re-perfusion injury may occur which is caused by free radicals being released from the mitochondria causing oxidation damage.
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