CSIM 1.3 Response to Cell Injury Flashcards
What affect does the amount or level of injury have on the fate of a cell?
The cell can either:
• Adapt in minor injury
• Die in severe injury
In which ways can cell death occur?
- Apoptosis
* Necrosis
In low levels of injury, in which ways can the cell ‘adapt’?
- Hydropic change
- Fat accumulation
- Atrophy
- Hypertrophy OR hyperplasia
- Metaplasia
What is hydropic change?
When does this most commonly occur?
Cells swelling with water in response to injury
When cells are depleted of ATP, and so the sodium potassium pumps can no longer regulate fluid content
Which cells undergo fat accumulation when damaged?
Liver cells
Briefly describe what is meant by necrosis
Non-energy-dependent cell death which involves rupturing of the cell membrane
What can cause cell atrophy?
- Hypoxia
- Reduced nutrition
- Decreased endocrine stimulation
- Decreased workload (use it or lose it)
What can cause hypertrophy?
- Increased functional demand
- Increased hormonal secretion
NB: bodybuilding doesn’t increase cell count, only increases the size of the muscle cells
What is metaplasia?
One adult cell type is replaced by another adult cell type. It can be epithelial –> epithelial, or mesenchymal –> mesenchymal
What causes metaplasia?
A change in environment which causes cell adaptation
What metaplasia can be induced by smoking?
Metaplasia of respiratory epithelium into squamous cells
Recall the types of necrosis
- Coagulative
- Colloquative
- Liquefactive
- Caseous
- Gangenous
Always pathological
What does necrosis cause in surrounding tissues?
Inflammatory responses
What two main events are characteristic of necrosis (rather than apoptosis)?
- Loss of membrane integrity
* Cell degradation by lysosomal enzymes
What is a penumbra?
The area surrounding an ischemic event (e.g. stroke) receives reduced blood flow and therefore oxygen , leading to ischaemia near to the original insult, amplifying the original damage from the ischaemia
Where is colloquative necrosis seen?
Only in the brain
What does caseous necrosis look like?
Casero cheese
What is gangrene a combination of?
Infection and infarction
How is gangrene treated?
Amputation
What is pathological calcification and what are the types of it?
Which diseases is each associated with?
Abnormal deposition of calcium salt:
• Dystrophic calcification (associated with necrosis)
• Metastatic calcification (associated with hypercalcaemia)
How is dystrophic calcification determined?
Abnormal deposition of calcium where serum calcium levels are normal but there is damaged tissue
How is metastatic calcification determined?
Abnormal deposition of calcium where serum calcium levels are high, and tissue is normal
What occurs in apoptosis?
- Is an ENERGY-DEPENDENT process
- Enzymatic destruction of DNA and sytoskeleton
- Cell membrane remains intact
- Cell fragments fall off (‘blebs’) and are phagocytosed
Does apoptosis occur in acute trauma?
No - it takes time to occur (cell needs to ‘decide’ to kill itself)
What are the two types of apoptosis?
Physiological
• Development and normal cell turnover
• Removes redundant or damaged cells
Pathological
• Eliminates potentially harmful cells
• Mutated cells or virally-infected cells undergo pathological apoptosis
How can you histologically identify a cell undergoing apoptosis?
- Dense nucleus
- Space around cell where it used to be
- Formation of apoptotic bodies (small purple granules)
IMG 24
What is ‘disease’?
A structural and functional morbidity causing symptoms
