2. Cell Injury Flashcards
what is involved in the maintenance of a steady state?
- preservation of genetic integrity
- normal enzyme content
- intact membranes and transmembrane proteins
- adequate supply of substrates and oxygen
what is the reaction of cell to stress?
initially tries to adapt. if it cannot, or if it exposed to an injurious stimulus, it gets injured
what are the 2 types of cell injury?
reversible (normal homeostasis)
irreversible
what are the 2 types of irreversible cell injury?
necrosis
apoptosis
what are the ways in which cells adapt to stress?
- change in cellular activity
2. change in cell morphology
in what ways can the cell alter its activity?
- increased activity
- physiological hypertrophy
- pathological hypertrophy
- physiological hyperplasia
- pathological hyperplasia - decreased activity
- physiological atrophy
- pathological atrophy
in what ways can the cell alter its morphology?
metaplasia
dysplasia
what is the possible aetiology of cell injury?
- irradiation, genetic disorders
- infectious organisms, chemical agents, lack of essential nutrients
- physical trauma
- oxygen availability
- immunological, ageing
in what ways can oxygen availability be a problem to cells?
hypoxia - less oxygen
anoxia - absence of oxygen
ischaemia - lack of blood flow, leading to hypoxia
hyperaemia, cyanide poisoning
how can the lack of oxygen availability be corrected?
re-oxygenation as a result of re-perfusion of the cell
how does physical trauma affect the cells?
causes disruption of cell structure and thrombosis, leads to ischaemia
the vacuum created sucks in dirt, leading to infection and sepsis
extremes of temperature can lead to the denaturation of proteins, formation of ice crystals, and fever
how can chemical agents harm cells?
different chemical agents have different modes of action and can harm the cell in different ways
give examples of harmful chemical agents to cells
alcohol tobacco drugs poisons environmental and occupational agents eg. asbestos
what is cyanide poisoning?
cyanide binds to cytochrome C oxidase on the ETC and inactivates it. therefore, it prevents the electron from binding to oxygen and the formation of ATP as well
how do bacteria harm cells?
releasing different types of toxins, classed into endotoxins and exotoxins
how do viruses harm cells?
hijack protein synthesis mechanism of cells, leading to cell lysis
how are cells affected by infectious organisms
their individual methods of harming cells, and collateral damage via inflammation
how does irradiation harm cells?
generates free radicals and therefore causes direct damage to macromolecules
which areas are more sensitive to irradiation?
bone marrow
gonads
intestines
which areas are less sensitive to irradiation?
uterus
adrenal glands
pancreas
when is an inflammatory response stimulated after being exposed to radiation?
several hours after
examples of radiation
x rays
UV light
radioactive particles
