Cell Injury Flashcards
how do cells try to adapt if they cannot return to homeostasis?
hyperplasia
hypertrophy
metaplasia
atrophy
what structures are the most vulnerable in the cell?
mitochondria
membranes
protein synthesis
cytoskeleton
genetic apparatus
appendices
what do ischemia or reduced circulating oxygen lead to?
hypoxic cell injury
what are the physical agents that can cause cell injury?
trauma
temperature
ionizing radiation
electricity
what are the different parts of nutritional imbalance that can cause cell injury?
starvation or hypoglycemia
obesity
vitamins and minerals
why is it important that often a metabolized intermediate of a chemical, drug, or toxin is the acting toxin?
basis for selective liver/kidney toxicity
what are two examples of immune responses invoking physiologic responses that damage cells?
anaphylaxis
suppurative necrosis
what causes age-related cell injury?
accumulation undigested cell products
telomere shortening
cumulative environmental stress maybe
what happens if the cell loses the Na/K pump?
sodium accumulates inside cell, potassium is lost
cell swelling
what leads to an influx of intracellular calcium?
depletion ATP
calcium pumps dependent upon ATP
leads to mitochondrial permeability transition
what does the mitochondria leak after taking damage from the influx of calcium, oxidative stress, and enzymatic damage to the phospholipid membrane?
cytochrome C which promotes apoptosis
why does anaerobic glycolysis after the ATP is depleted cause problems?
lactic acid builds up
ribosomes dissociate
free radical formation
what leads to the increased free radicals?
overwhelmed reactive oxygen species scavaging systems
what controls free radicals?
antioxidants
iron and copper binding proteins
what enzyme is important in free radical scavenging?
glutathione peroxidase
what are the results of free radical accumulation?
lipid peroxidation
DNA lesions
protein modification
what are two examples of membrane toxins?
bacterial hemolysin
complement granzyme
what is the Unfolded Protein Response?
upregulation of genes for protein folding
prolonged UPR activation: oxidative stress and cell death (reactive oxygen species)
what is the earliest indicator of non-lethal, potentially reversible cell injury?
hydropic degeneration
what is steatosis?
fatty change (reversible cell injury)
what can lead to hypoxic cell injury?
ischemia
reduced circulating oxygen
respiratory chain failure
what can lead to reduced circulating oxygen?
anemia
carbon monoxide
heart disease
what can electricity do to cells?
cell injury:
impaired pumps and signaling
vascular injury: delayed fulminant pulmonary edema
where might chemicals, drugs, and toxins attack in the cell?
membranes
receptors
ion exchange pumps
mitochondria
what causes an increase in misfolded proteins?
environmental factors
excessive nitric oxide
reactive oxygen species
what can cause ischemia?
thrombosis/thromboembolism
hypotension
what are the especially vulnerable cell populations to hypoxic cell injury?
neurons
hepatocytes
cardiac myocytes
renal tubular epithelium
others
what are the two methods for immune-mediated injury?
immune cells attack other cells or their products directly
immune response may invoke a physiologic response that damages cells
what are the antioxidants that help control free radicals?
vitamin E
selenium
vitamin A
ascorbic acid
glutathione
what are the iron and copper binding proteins?
transferrin
ferritin
lactoferrin
ceruloplasmin
how do free radicals hinder the membranes?
attack double bonds in fatty acids
produce peroxides which further destabilize
how do free radicals modify proteins?
oxidize amino acid side chains
protein-protein cross linkages
oxidize protein backbone
what can mediate protein misfolding?
environmental factors
excessive nitric oxide
reactive oxygen species
what can cause steatosis?
metabolic injury
toxins
hypoxia
