Cell responses to injury Flashcards
what is adaptation?
- Reversible process which occurs when there is stress to a cell
- Can be physiological or pathological
- Once stimulus goes, it goes back to normal
what happens if the cells have an inability to adapt during adaptation?
cell injury
what are the 5 types of cellular adaptation?
- hypertrophy
- hyperplasia
- atrophy
- metaplasia
- dysplasia
why does hypertrophy occur?
increase in protein synthesis, leading to increase organelle production and growth factor
what is hypertrophy?
increase
hyperplasia of the thyroid is related to what deficiency?
iodine deficiency
what is atrophy
decrease in cell size
what is metaplasia?
change of one cell type to another
what is dysplasia?
abnormality in the formation of a tissue
name some causes of cell injury?
- oxygen deprivation
- physical agents
- chemical agents and drugs
- infectious agents
- immunological reactions
- genetic abnormalities
- nutritional imbalances
what is hypoxia?
oxygen deprivation
hypoxia can happen due to what 3 points?
- reduced blood flow (ishemia)
- inadequate oxygenation of blood
- decreased oxygen carrying capacity
what is a reperfusion injury?
restoration of blood flow after ischemia or lack of blood flow that leads to oxidative stress, inflammation, intracellular calcium overload, ROS
what 2 ways can chemical agents injure a cell and explain?
- direct toxicity= goes straight to cell and injures it
- conversion of toxic metabolites= chemical enters body and is changed to metabolites that cause injury due to membrane damage and formation of ROS
what are the 4 physical agents that can cause cell death?
- mechanical
- radiation
- extreme temperatures
- electric shock
what’s infectious agents can cause cell injury/death?
- parasites
- prions
- viruses
- fungi
- bacteria
what immunological reactions can cause cell injury/death?
- reactions to self-antigens = autoimmune disease
- external agents e.g allergies
how can genetics lead to cell injury/death?
- deficient protein function
- misfolded proteins
- accumulation of damaged DNA
how can nutritional imbalances cause cell injury/death?
- obesity
- under nutrition
what does causes of cell injury depend on?
- nature of injury
- duration of injury
- severity of injury
what are the 4 mechanisms of cell injury?
- mitochondria damage leading to ATP depletion
- cell membrane damage
- disruption of biochemical pathways
- DNA damage
describe the mechanism of mitochondrial damage in relation to cell injury
- caused mainly by production of ROS (reactive oxygen species)
- formation of channels leads to release of CALCIUM into cytosol
- oxygen deprivation/ ATP depletion
- mutation of mitochondrial genes
how can DNA be damaged
- radiation
- drugs
- ROS
- Aging
- Chemotherapeutics
what is a reversible injury?
functional and structural alterations in mild forms of injury, these can resolve if the stimulus is removed
Describe physical changes which comes with reversible cell injuries
- Pallor
- increased rugor
- increased weight
