Pathology (Cell Injury and Death) Flashcards
What are the causes of cellular injury?
Oxygen deprivation: hypoxia, ischaemia
Physical agents
Chemical agents and drugs
Infectious agents
Immunological reactions
Genetic dearangements
Nutritional imbalances
Describe the pathways in which a healthy cell can take
(Hint: Picture)
List 5 Biochemical mechanisms to cell death.
ATP depletion
Oxygen and oxygen derived free radicals
Intracellular calcium and loss of calcium homeostasis
Defects in membrane permeability
Irreversible mitochondrial damage
What are the 4 primary targets for cell death?
Mitochondria (hypoxia and hypoglycemia)
Cell membranes (oxygen free radicals)
Cytoskeleton (immune mediated)
Cellular DNA (oxygen free radicals)
List 3 (of 7) Reversible cell injuries
O2 and ATP drops
Anaerobic glycolysis
Lactic acid and pH drop
The Na pump failure Na
Na and water in cytoplasm
Swelling and dlation of the ER
Disruption inhibits protein synthesis
What are causes of Irreversible cell injury?
Calcium activates certain enzymes such as phospholipases, proteases, ATPases and endonucleases.
Rupture of lysosomes and autolysis
Myelin figures
Defects in cell membrane
Mitochondrial swelling
What is Pyknosis?
Smaller, condensed, stained with haemotoxylin of nucleus
What is Karyorrhexis?
Fragmentation of nuclei
What is Karyolysis?
Complete breakdown of nucleus
Name three Free Radical species?
Superoxide anion O2-
Hydroxyl radical OH
Hydrogen Peroxide H2O2
How do free radicals damage cells?
Peroxidation of lipid mebranes
Attack thiol groups on proteins
Breakdown DNA
NADPH depletion of mitochondria, leads to calcium in cytosol.
What do free radicals react with?
Cell membranes
Proteins
DNA
Mitochondria release Ca into cytoplasm.
Are there protective mechanism of free radicals? If so list some.
Yes.
Antioxidants e.g. Vit E
Glutathione Peroxidase
Superoxide dismutase
Catalase
What is the morphology of Necrosis?
Cellular swelling
Nuclear and cytoplasmic degradation
Coagulative
Liquidifactive
Caseous
Fatty
What is coagulative necrosis?
Outline of cells and architecture of tissue still seen.
What is liquefactive necrosis?
Semi-liquid as the result of action of hydrolytic enzymes.
What is caseous necrosis?
Dead tissue that resembles cream cheese: characteristic of tuberculosis.
What is fat necrosis?
Can occur after liberation of pancreatic enzymes and after trauma to fat tissue.
When is apoptosis applicable?
During development
Maintaining cell populations
Defence against invading pathogens and tumour cells
Removal of damaged cells
Natural aging
How is apoptosis important in development?
Without apoptosis we wouldn’t have the distinctive fingers and toes that we have. We would instead have webbing between them.
How is apoptosis important in homeostasis?
Regulation of cells - e.g. in the intestine
Tumour killing
Removal of viral infected cells
Removal of injured cells - e.g. viral hepatitis
Atopy of organs - obstruction of pancreas, kidney
Define hypertrophy
Increase in cell size
Increased synthesis of structural components
No cell division
e.g. Arnold Schwarzenegger and muscle
Define hyperplasia
Increase in cell numbers
Distinct from hyperstrophy but they may occur together
e.g. calluses
Define metaplasia
Change in cell phenotype
Certain long standing environmental changes have adverse effects on specialised cell types
e.g. barretts oesophagus
Smoking and bronchial epithelium
Define dysplasia
Change to abnormal cell phenotype
Define neoplasia
Uncontrolled growth of abnormal cell phenotype.
Some adaptive responses in cellular adaption are?
Changes in cell size and growth
Changes in cellular differentiation
Intracellular accumulation
What are labile or stable cells?
Can divide easily and undergo hyperplasia
What are permanent cells?
Cannot divide after birth
Cannot undergo hyperplasia
Can undergo hypertrophy
What is atrophy?
Decrease in size and activity of cell
Diminished function
Are not dead and removal of stimulus often causes the cell to revert to normal
What are 4 (of 7) pathological causes of atrophy?
Disuse
Denervation
Inadequate nutrition
Loss of endrocrine stimulation
Diminished blood supply
Senile atrophy
Pressure atrophy
How does metaplasia occur?
Stem cells are present in most epitheli
These reverse cells are undifferentiated
These undifferentiated mesenchymall cells respond to signals
Intracellular Accumulations: Name what it is, an example of where it occurs, and the causes behind this site.
One of the manifestations of metabolic disturbance is the accumulation of material within cells.
A normal cellular constituent
An abnormal substance
or pigment
Liver cells collecting fat due to alcohol consumption
Toxins
Protein malnutrition
Diabetes
Obesity
Anoxia
Alcohol
