MBC - Cell Fate and Injury Flashcards
How do cells die?
Cell injury
How do cells get injured?
Either through an injurious stimulus or an inability to adapt to a stress/increased demand
What is lethal injury?
Injury which leads to death
What is sub- lethal injury?
Reversible injury or can lead to cell death
Explain how a cardiac myocyte responds to a stress?
It may either increase in size (hypertrophy) in response to increased load (stress), or injury such as ischaemia may cause reversible injury. Continued ischaemia will then cause cell death.
What are the 8 causes of cell injury with examples?
Ageing - acquisition of changes/mutation Physical agents - e.g. gunshot trauma Immunological reactions Genetic defects e.g. SCD Chemical agent e.g. weed killer Oxygen deprivation Infection agents e.g. viruses Nutritional e.g. obesity/starvation/malnutrition
How would oxygen deprivation cause myocardial infarction?
Ischaemia from coronary heart disease will arise from atheromatous plaque, this leads to oxygen deprivation and subsequent cell death.
What factors affect the cell response to injurious stimuli?
Type of injury
Duration
Severity
What do the consequence of the stimuli themselves depend on?
- Cell type - e.g. bone cells can survive without O2 much quicker than nerve cells.
- Status - proliferating cells are much more prone to mutating
What are the 4 vulnerable intracellular mechanisms?
ATP production
Cell membrane integrity
Protein synthesis
Integrity of genetic apparatus
How would damage to cell membrane integrity or ATP production arise?
Rapidly/almost immediately
How would damage to protein synthesis or DNA damage arise?
May show up in the later stages of life
How are ATP production and membrane integrity interlinked?
ATP production being affected will lead to the cell’s inability to maintain its membrane, thus compromising its integrity. Loss in membrane integrity may then cause a loss in intracellular regulation, thus having a negative effect on ATP production. Processes are inter-dependent
Give on example where injury precedes death, and death precedes morphology changing.
For example, myocytes will stop contracting having been injured and before cell death. Following cell death, they will undergo morphological changes.
What is atrophy?
A shrinkage in cell/organ size due to a loss in cell substance.
Give an example of atrophy.
Alzheimer’s - cerebrocortical atrophy
Muscle denervation leads to muscle atrophy.
What is hypertrophy?
Increase in cell size and thus organ size
What is the difference between physiological and pathological hypertrophy? (use examples)
- Physiological hypertrophy is normal in healthy individuals e.g. an increase in uterus size during pregnancy.
- Pathological hypertrophy is part of disease process e.g. cardiac myocytes increase in size due to abnormal increases in demand
How does hypertrophy come about?
Can occur as a result of increased functional demand or some sort of hormonal stimulus.
What is hyperplasia?
Increase of cell number in an organ.