inflammatory process Flashcards
cell characteristics
cells tend to preserve their environment to maintain homeostasis (body wants to go back to normal ASAP). Physiologic stress or pathologic stimuli cause cells to undergo adaptation and find a new steady state to preserve viability
physiologic stress
stimulation of cells to do something different so cells begin to change. ex. lifting weights at the gym
pathologic stimuli
rupturing of cells from too much stress ex. bowed tendon
atrophy
decrease in cell size, but cells are still there
hypertrophy
increase in cell size by increasing exercise or use
hyperplasia
increase in cell number. May be caused by pregnancy (in uterus/udder) or cancer (tumor)
metaplasia
change in cell type, may change back to original cell type. ex. cigarette smokers (normal cells in trachea have cilia but smokers do not have ciliated cells because they are more resistant to smoke)
is injury reversible?
injury can be reversible, but with persistent or severe stress (ex. broken leg), injury is irreversible (results in cell death)
Necrosis
loss of blood supply or exposure to toxins, cellular swelling, protein denaturation and tissue dysfunction results
apoptosis
programmed cell death, dead cells are removed with minimal disruption of the surrounding tissue
Causes of Cell Injury
- oxygen deprevation (hypoxia) 2. chemical agents 3. infectious agents 4. genetic defects 5.immunologic reactions 6. nutritional imbalance 7. physical agents 8. aging
ischemia
oxygen deprivation, loss of blood supply in tissue due to impeded arterial flow or reduced venous drainage ex. cut, atheriosclerosis, embolism
inadequate oxygenation
type of oxygen deprevation, ex. pneumonia and emphysema
reduced O2 carrying capacity of blood
ex. anemia, loss of red blood cells
chemical agents
any chemical substance can cause cell injury (even salt and water). ethanol causes liver injury that is reversible at first but chronic ethanol use will lead to irreversible injury (liver exhaustion=cerosis)
infectious agent
ex. virus, bacteria, worms, fungi, protozoan
genetic defects
may result in pathologic changes ex. lethal white
immunologic reactions
anaphylactic shock is classical example of an exaggerated immune response, auto-immune disease which is loss of self-tolerance (lupus, rheumatoid arthritis)
anaphylactic shock
disregulated allergy causing an exaggerated immune response (causes swelling in throat, asphyxiation and death)