Flashcards in Cell injury Deck (28):
what is lethal cell injury?
produces cell death
what is sublethal cell injury?
produces injury not amounting to cell death - may be reversible or may progress to cell death
list the 8 causes of cell injury
1) Oxygen deprivation
2) Chemical agents
3) Infectious agents
4) Nutritional imbalances
5) Physical agents
6) Immunological reactions
8) Genetic defects
oxygen came into nuts, particularly ice age generation
what does the cellular response to injurious stimuli depend on?
- the type of injury
- the duration
- the severity
what do the consequences of an injurious stimuli depend on?
- the type of cell
- the status of that cell
- its adaptability
- its genetic makeup
what 4 intracellular systems are particularly vulnerable and often interlinked?
1) cell membrane integrity
2) ATP generation
3) protein synthesis
4) the integrity of the genetic apparatus (DNA and RNA)
list the 6 cellular adaptations to injury
what is atrophy?
shrinkage in the size of the cell (or organ) by the loss of cell substance but the same number of cells are present
give 2 examples of atrophy
- brain atrophy (dementia)
- muscle atrophy
what is hypertrophy?
increase in the size of cells and consequently an increase in the size of the organ, caused by increased functional demand or specific hormone stimulation, which can be physiological or pathological
give examples of physiological hypertrophy
- heart size increasing due to pregnancy
- heart size increasing in athletes
- hypertrophy of the uterus during pregancy
give an example of pathological hypertrophy
- heart size increasing to due to raised BP
what is hyperplasia?
an increase in the number of cells in an organ, which can be physiological or pathological
what is physiological hyperplasia?
hormonal or compensatory
what is pathological hyperplasia?
due to excessive hormonal stimulation or growth factor stimulation
give an example of physiological hyperplasia
give an example of pathological hyperplasia
what is metaplasia?
a reversible change in which one adult cell type is replaced by another, which can be either physiological or pathological
give an example of physiological metaplasia
at puberty/during pregnancy the cervical canal opens up resulting in columnar cells becoming squamous for some time
what is dysplasia?
precancerous cells which show the genetic and cytological features of malignancy due to increased mitosis, but not invading the underlying tissue
what is attempted at the dysplasia stage?
screening to diagnose cancer at it leads to more successful treatment
what are the light microscopic changes associated with reversible injury?
- fatty change: alcoholic fatty change due to excessive alcohol consumption, leading to liver disease
- cellular swelling: ballooning degeneration due to damage of the cell membrane
what are the light microscopic changes associated with irreversible injury?
- coagulative necrosis: cells are dead but still visible (e.g. during MI)
- liquefactive necrosis: normal cell structure disappears (e.g. in cerebral infarction)
- caseous necrosis: "cheesy" necrosis resulting in normal cell structure disappearing but granular materials remaining (e.g. in pulmonary TB)
- fat necrosis: a result of inflammation of the pancreas - when the pancreas is damaged lipase is released
what is necrosis?
confluent cell death (death of cells next to each other) associated with inflammation
what is apoptosis?
programmed, single cell death with no inflammation, which is energy dependent and where cells are phagocytized by macrophages
what are the causes of apoptosis?
- deletion of auto-reactive T cells in the thymus
- hormone-dependent physiological involution
- cell deletion in proliferating populations
- a variety of mild injurious stimuli that cause irreparable DNA damage that triggers cell suicide pathways
list 3 differences between apoptosis and necrosis
1) apoptosis may be physiological, necrosis is not
2) apoptosis is an active energy dependent process, necrosis is not
3) apoptosis is not associated with inflammation, necrosis is