cell injury Flashcards
cell injury can be reversible or irreversible, what are the characteristics of reversible cell injury?
- cells adapt to change sin environment
- return to normal once stimuli removed
cell injury can be reversible or irreversible, what are the characteristics of irreversible cell injury?
- permanent
- cell death
which factors determine whether cell injury is reversible or irreversible?
- cell type
- duration
- severity
- susceptibility/adaptabilty of cell (nutritional status)
give examples of some causes of cell injury
- hypoxia
- physical agents
- chemicals
- infection
- immunological reaction
what is hypoxia?
decreased oxygen
which conditions may hypoxia cause?
- anaemia
- reparatory failure
what effect does hypoxia have on cell respiration?
decreased ATP as cell cannot aerobically respire, cell still capable of anaerobic respiration
what is ischaemia?
decreased blood flow to tissues
what is more severe, hypoxia or ischaemia?
ischaemia
give an example of a condition caused as a result of ischaemia
atherosclerosis
what effect does iscghaemia have on cell respiration?
no aerobic or anaerobic respiration
give examples of physical agents which may cause cell injury
- mechanical trauma (affect cell structure)
- temp (affect proteins, chemical reaction)
- ionising radiation (DNA damage)
- electric shock
give examples of infectious agents which may cause cell injury
bacteria, fungi, parasite, virus, proton
give examples of chemical agents which may cause cell injury
- simple chemical (i.e glucose in excess may cause osmotic imbalance)
- poison
- asbestos (inflammation)
- alcohol, smoking, recreational drugs
reversible injury may cause disruption to ?
- respiration
- plasma membrane integrity
- protein synthesis
- DNA maintenance
what morphological changes may occur as a result of reversible cell injury?
- cloudy swelling
- fatty changes
what happens to a cloudy swollen cell?
- incapable of maintaining ionic and fluid homeostasis
- failure of energy dependant ion pumps leading to influx of Na and water
- build up of intracellular metabolites
how does fatty change occur in an injured cell ?
accumulation of lipid vacuoles in cytoplasm by disruption to fatty acid metabolism
what type of cell injury causes fatty changes?
toxic and hypoxic
what systemic effect does fatty changes to a cell have?
enlarged and pale liver
what is the definition of necrosis?
cell death due to pathology
what happens during necrosis?
- intracellular protein denaturation & lysosomal digestion of cell
- cell membrane disputed so contents leak
which cell death, apoptosis or necrosis, always involves an inflammatory response?
necrosis
which cell death, apoptosis or necrosis, never involves an inflammatory response?
apoptosis
what microscopical changes occur as a result of necrosis?
- pyknosis (nucleus shrinks)
- karyorrhexis (nucleus fragments)
if necrotic remains are not removed, what occurs?
Ca salts deposited in necrotic tissue
which cell death, apoptosis or necrosis, requires energy?
apoptosis
what is apoptosis?
programmed cell death
what are the pathological triggers of apoptosis?
- hypoxia/ischaemia
- viral infection
- DNA damage (unrepeatable p53)
- caspases trigger it
give some physiological roles of apoptosis
- deletion of self reactive lymphocytes in thymus
- maintain constant number of cells
- delete inflammatory cells after inflammation
describe some morphological feature of apoptosis
- cell shrinkage
- chromatin condenses
- membrane intact
which cell death, apoptosis or necrosis results in enlarged cell size?
necrosis
which cell death, apoptosis or necrosis results in reduced cell size?
apoptosis
which cell death, apoptosis or necrosis results in disrupted membrane?
necrosis
which cell death, apoptosis or necrosis results in intact contents?
apoptosis
which cell death, apoptosis or necrosis has a physiological role?
apoptosis
what is amyloid?
fibrillar protein that is deposited in the liver, kidneys, spleen, or other tissues due to pathology
name the 3 types of amyloid protein
- AL (amyloid light chain)
- AA (amyloid associated)
- ABeta ( alzheimers disease)
what is pathological pigmentation?
build up of pigmented substances in cytoplasm
give examples of endogenous pigmentation
- haemosiderin (bruise)
- melanin
give examples of exogenous pigmentation
- carbons deposits in macrophages of alveoli (anthracosis)
- tattoo
- heavy metal salts
- intravascular drug use
what is pathological calcification?
a lesion in which calcium salts, usually in the form of calcium phosphate, are deposited abnormally in soft tissues
what are the the 2 forms of pathological calcification?
- dystrophic
- metastatic
what is is dystropic pathological calcification?
Ca phosphate in necrotic tissue
what is metastatic pathological calcification?
Ca salts in vital tissue (connective, BV)
what causes pathological calcification?
- increased parathyroid hormone, parathyroid tumour
- destruction bone tissue
- excess vit D
- renal failure
state the differences between apoptosis and necrosis
apoptosis - no inflammation, requires energy, cell shrinks, plasma membrane
necrosis - inflammation, no energy, plasma membrane disrupted
state 2 microscopical characteristics of cellular reversible injury?
- fatty changes
- cloudy swelling
