Cell Injury, Degeneration and Death Flashcards
List 6 causes of cell injury?
Mechanical/trauma Chemicals Infection Hypoxia Immunological Genetics
Describe the pathogensis of cell injury on the; mitochondria membrane nucleus cytoplasm and ribosomes?
- Mitochondria: Disrupted anaerobic respiration and decreased ATP synthesis
- Membrane: disruptions causing problems with ion concentrations
- nucleus: problems with DNA maintenance or DNA damage
- Cytoplasm/ribosomes: Poor enzyme/protein synthesis
What is oxidative stress?
Cell injury due to excess reactive oxygen species.
Where is ROS normally produced in small amounts?
In respiration
List 3 factors that could cause an increase in ROS production in a cell?
Damage by radiation, toxic chemicals or hypoxia.
Why would malnutrition exacerbate oxidative stress?
Less protective antioxidants.
List 3 features of reversible cell injury?
Cloudy swelling: Membrane problem with energy dependant Na+ pumps causing Na+ influx and build up of intracellular metabolites.
Cytoplasmic blebs: Disrupted microvilli and swollen mitochondria.
Fatty change: Lipid vacuoles in cytoplasm and disruption of fatty acid metobolism.
Describe key features of necrosis?
Unpogrammed cell death.
Always pathological.
Features: Cell swelling, vacuole formation, disruption of organelle membranes and the plasma membrane.
Cell lysis and leakage - intracellular things such as ezymes damage adjacent cells and cause inflammation.
Dna disruption.
Hydrolysis.
What nuclear changes could be seen in necrosis?
Nuclear fading: Chromatin condensation
Nuclear shrinkage: DNA condensation
Nuclear fragmentation: nuclear membrane rupture.
List the 4 types of necrosis and their features. Give an example for each?
Coagulative: Appears firm, due to loss of blood e.g. haemorrhage.
Colliquitive: Tissue becomes liquidy due to release of neutrophil contents e.g. in infection.
Caseous: Tissue appears soft and cheese like. E.g. TB due to the ‘walling off’ of infection so marcophages can attack it.
Fatty: Due to action of lipases on fatty tissue. e.g. in pancreatitis when enzymes are released.
Describe apoptosis?
Normally programmed cell death.
Uses energy and follows distinct pathways.
Can be physiological: embyogenesis, normal cell turnover.
or seen in pathological circumstances: viral infection, hypoxia.
You get cell shrinkage, chromatin condensation and cytoplasmic blebs - which break off and form apoptotic bodies which can be phagocytosed by macrophages.
What is a deposition?
Abnormal accumulation of a substance.
Gie examples of endogenous depositions?
Calcium, lipid, collagen (fibrosis), melanin.
Give examples of exogenous depositions?
Tattoo ink, carbon, asbestos.
What causes amyloid depositions?
Abnormal folding of soluable protein fibrils into abnormal insoluable aggregates.
