Unit 1 Flashcards
Etiology
Underlying causes and modifying factors responsible for the initiation and progression of disease
Pathogenesis
mechanisms of development and progression of disease, account for the cellular and molecular changes that give rise to the specific functional and structural abnormalities that characterize any disease
What are 8 causes of Cell injury?
- hypoxia and ischemia
- toxins
- infectious agents
- immunologic reactions
- Genetic abnormalities
- Nutrient imbalances
- Physical agents
- Aging
What is hypoxia and what is ischemia?
hypoxia refferes to oxyegen deficiency and ischemia is a reduced blood supply. The most common cause of hypoxia is ischemia from an arterial obstruction. Both deprive tissues of oxygen but ischemia also results in nutrient deficiencies
Describe reversible injury
the stage of cell injury at which deranged function and morphology of the injured cells can return to normal if the damaging stimulus is removed
why do cells in reversible cell injury usually become swollen?
they intake water as a result of the failure of energy dependent ion pumps in the plasma membrane, leading to inability to maintain ionic and fluid homeostasis
Cellular swelling is due to increased _________ of the ________ _________
permeability of the plasma membrane
what are the two main morphological changes that occur with reversible cell injury?
- cellular swelling
2. fatty change
what is fatty change?
especially in organs that are involved in lipid metabolism such as the liver, triglyceride containing lipid vacuoles in the cytoplasm
The cytoplasm of injured cells may also become more _________ (redder) with progression towards necrosis
eosinophilic
what are 4 other morphological changes during cellular injury?
- plasma membrane alterations (blebbing, blunting etc)
- mitochondrial changes such as swelling and phospholipid rich densities
- dilation of the ER
- nuclear alterations such as clumping of chromatin
normal cell function depends on what ?
nutrients, oxygen glucose, amino acids, and removal of wastes
when the adaptive ability of the cell is exceeded cell ______ develops
injury
mild cell injury leads to _____ changes but if more injury occurs then _______ follows
functional changes then degeneration
what is a static state with cell injury?
they function at a sub optimal level
compensated state
insufficient function is sufficient to maintain life of the body
irreversible cell injury is characterized by changes at the __________ level
microscopic
do necrotic cells function?
no
necrosis in living organims
local cell death
somatic death
death of whole body
what ate the most important targets of injurious stimuli are ?
the mitochondria sites of ATP generation, cell membranes, protein synthesis, cytoskeleton, cell genetic apparatus
what are the overall 4 mechanisms of cell degeneration?
- Depletion of ATP
- impaired cell membrane function
- intracellular accumulations
- genetic abnormalities
what are some ways impaired cell energy production can occur?
hypoxia, hypoglycemia, enzyme inhibition, uncoupling of oxidation phosphorylation
hypoxemia
decrease ability of blood to carry oxyegn or insuficient hemoglobin to bind oxygen
hypoglycemia
low glucose levels in the blood
enzyme inhibition
anything which interfers with vital enzymes in the repiratory chain will lead to insuficient ATP
uncoupling oxidative phosphorylation
anything that alters how enzymes and chemical reactions are organized on the mitochondrial membrane will lead to decreased ATP production
cells have a _________ concentration of some solutes than surrounding environment
higher
with impaired energy production cells _____ water
gain
why does intracellular accumulation of water occur?
because lack of ATP leads to dysfunction of cell membrane and sodium pump, sodium and water moves in the cell
swelling of mitochondria causes what?
uncoupling of oxidative phosphorylation, alters arrangement of respiratory enzymes of mitochondria
why would cells switch to anaerobic glycolysis?
if a lack of oxygen has led to impaired energy, production of lactic acid occurs
defective energy production affects which cells first?
those with the highest metabolic rate, highest oxygen demand
ex. brain cells
cell membrane damage is caused by _____ ________
free radicals
free radicals
highly reactive particles haveing an unpaired electron in their outer shell, also known as oxidative stress, by product of metabolism
final compounds of the activated complement pathway can lead to _____ ________ _______
damaged cell membranes
what causes direct lysis of the cell membrane?
enzymes with lipase acitivity, certain viruses, physical and chemical agents
cell shape changes from bioconcave to _________ with impaired membrane function
spherocytes (spheroidal)
how does deposition of lipofuscin occur?
resulted from free radical peroxidation of lipids in subcellular membranes
deleterious effects can be ________ or ________
exogenous (outisde) or endogenous (inside)
what are exogenous injurious agents usually from?
drugs toxic chemicals, heavy metals, infectious agents etc
triglyceride accumate in the cytoplasm of parenchymal cells in organs such as the liver this is called what?
fatty degradation, fatty change or steatosis
when does fatty liver disease occur?
when free fatty acids are carried in the portal blood from the intestine to the liver where they are processed to form triglycerides, phospholipids and cholesterol esters