Injuries to cells Flashcards
Name the 5 branches of pathology
Histology Haemotology Immunology Chemical pathology Microbiology
Name the to ways cells respond to stress
Adaption
Injury
Injury can be either
Reversible
Irreversible
If injury is irreversible this results in what?
Cell death
What are the two types of cell death?
Apoptosis
Necrosis
Name the different types of cell adaption…
Hyperplasia
Hypertrophy
Atrophy
Metplasia
Define hyperplasia
Increase in cell number
(Can lead to hypertrophy)
Can be pathological/physiological
Define hypertrophy
Increase in cell size
(Can cause increase size of organ)
Can be pathological/physiological
Define atrophy
Decrease in cell size
What can cause atrophy?
Decrease workload Decrease blood supply Inadequate nutrition Loss of hormonal stimulus Ageing
Define metplasia
One cell replaced by another cell
E.g. oesophagus
*Can be reversible
What are the 3 most common causes of cellular injury
Hypoxia (low o2)
Ischaemia (loss of blood supply)
Chemical damage (alcohol etc)
Name other causes of cellular injury
Radiation Lack of nutrients Infection Ageing Immunological changes
What are the 2 most common finding within reversible cellular injury (morphology)?
Cellular swelling
Fatty change
Out of necrosis and apoptosis which process is ALWAYS pathological?
Necrosis
Out of necrosis and apoptosis which causes local inflammation and why?
Necrosis due to cell swelling of cell that then ruptures
Out of necrosis and apoptosis which is known as a programmed cell death?
Apoptosis
Why does necrosis occur?
Due to damage of the cell membrane which then allows enzymes to digest the cell
Name a common type of necrosis…
Ischaemic necrosis
What causes apoptosis…
Damage to DNA/protein structures resulting in cell death
State the process of apoptosis…
Cell starts to break into small fragments
Fragments have signals on them that attract resident macrophages
Resident macrophages come and phagocytose
No cellular leakage meaning no danger of inflammatory response
Physiological apoptosis is meant to occur when?
Embryogenesis (excess tissue is programmed to die away if this doesn’t happen this is bad)
Involution of hormone dependant tissues upon hormone deprivation (e.g. uterus post menopause becomes atrophic and small)
Elimination of cells after they have served their purpose
Elimination of potentially self-reactive lymphocytes
When does pathological apoptosis occur?
DNA damage Accumulation of misfiled proteins Infection Cell death induced by cytotoxic T cells Pathological atrophy in parenchymal organs after duct obstruction
Apoptosis results from what type of enzymes?
Caspases
What are the 2 main pathways that result in activation cell death pathway?
Mitrochondrial pathway (intrinsic) Fas death receptor pathway (extrinsic)
Name the 4 main types of necrosis
Coagulative (commonly occurs after infections/loss of blood supply- most common- causes heart attack/myocardial infarct)
Fat (death of fat tissue due to activation of lypases)
Caseous (usually means TB unless proven otherwise)
Liquefactive (typical of the brain when infarct- hole in the brain)
How do cells become injured?
ATP depletion Mitchondrial damage Influx of calcium Oxidative stress Damage of cell membrane DNA damage Intracellular accumulation of abnormal material e.g fat cholesterol and proteins
ATP depletion causes what?
Decrease in cellular energy
It also effects sodium pump which can cause electrolyte imbalances
Mitochondrial damage results in what?
Decreased levels of ATP
An influx of calcium leads to what?
Activation of enzymes which can trigger apoptosis and programme cell death
Damage to cell membrane results in what?
Necrosis
Give an example of DNA damage
Radiation
Give the 3 examples of accumulation of abnormal materials
Fat
Cholesterol
Protein
