cell injury + inflammation Flashcards
lecture 1
list some factors influencing healing
- physiological variables
- general health of individual
- comorbid presence (diabetes, alzheimer’s, incontinence, cancer)
- type of tissue
causes of cell injuries
- Ischemia
- Infectious Agents
- Immune Reactions
- Genetic Factors
- Nutritional Factors
- Physical Factors
- Chemical Factors
- Psychosocial Factors
Ischemia - Cell Injury
when blood flow is insufficient enough to maintain cell function and keep homeostasis, leading to apoxia [total reduction of o2] or hypoxia [partial reduction]
what happens as a result of hypoxia or anoxia [ischemia]?
insufficient oxygen to the body limits blood flow and o2 supply, leading to loss of aerobic metabolism and reduction in ATP synthesis
*accumulation of ions and fluids ——-> swelling of cells —> compromising function
causes of ischemia
- atherosclerosis
- suffocation
- pneumonia
- thrombus (clot)
- anemia (inadequate transport of O2]
- CO poisoning
infectious agents [cell injury]
which one is more common?
how do viruses kill?
- bacteria is the most common infectious agent, they release exotoxins
- viruses kill through cytopathic and indirect cytopathic effects
chemical reactions - infectious diseases
methods + define
defined: substances that injure cells
methods:
- directly (ex: mercury)
- indirect: substances that require metabolic transformation into toxic agent (ex: drugs)
Free Radicals (chemical factors)
- “unstable o2 molecules” - an O2 loses one of their electrons
- overproduction can lead to cell injury and death AKA oxidative stress (factors in 90% of diseases)
Antioxidants
foods that contain antioxidants
exogenous antioxidants
endogenous antioxidants
body responses to neutralize free radicals
exogenous: vitamin c, lycopene
endogenous: enzymes
causes of free radical formation
- UV rays
- pollutants
- drug overdose
- prolonged exercise
Genetic Factors - Cell Injury
alterations to the structure or number of chromosomes can induce abnormalities
single mutations defined & example
can cause changes in the amount and function of proteins
ex: sickle-cell anemia
environment + multiple gene mutation examples
hypertension
diabetes 2
mechanical factors can lead to…
typical tissues response to physical stress includes decreased stress tolerance and increased stress tolerance
causes of tissue injury - mechanical factors
- repeated episodes of magnitude force
- slow degradation of tissue tolerance
- low loads sustained over long periods
nutritional factors - kwashiorkor
protein malnutrition
extremes of physical factors
- electricity
- temperature
- radiation
physical factors
blunt or penetrating trauma, survivors may die later due to infections or organ failure
what is a prime target for age-related changes?
mitochondrial DNA
lipofuscin - cellular aging
aging-pigment granule (lipid) is higher concentrations in older cells
types of cellular aging
- reversible
- irreversible
adaptations of cell injury
- hyperplasia
- dysplasia
- hypertrophy
- atrophy
- metaplasia
hyperplasia
increased number of cells
dysplasia
increase in number of cells and change of morphology, loss of histologic organization