Chapter 3: Cellular Adaptation, Injury, and Death Flashcards
Learning Objectives
- Cite the general purpose of changes in cell structure and function that occur as the result of normal adaptive processes.
- Describe cell changes that occur with atrophy, hypertrophy, hyperplasia, metaplasia, and dysplasia, and state general conditions under which the changes occur.
- Compare the pathogenesis and effects of dystrophic and metastatic calcifications.
- Relate free radical formation and oxidative stress to cell injury and death.
- Differentiate cell death by apoptosis versus necrosis and gangrene.
In what ways do cells adapt to their environment (3)
- size (atrophy and hypertrophy)
- number (hyperplasia)
- form (metaplasia & dysplasia)
Atrophy v Hypertrophy
cell adaptation where a cell can either shrink or grow in size
hyperplasia
cell adaptation that features an increase in the number # of cells
can be good or bad
- good: scar tissue, pregnancy (uterus)
-bad: hormonal stimuli –> prostate cancer
metaplasia v dysplasia
cell adaptation where a cell either
becomes a different cell type (meta)
- reversible
- ex: smokers GI tract and lungs change from columnar to stratified
becomes damaged/deranged (dysplasia)
- usually changed by disease
- objective of a PAP smear
what are the different types of intracellular accumulations
- normal bodily substances
- lipids, proteins, carbs, melanin (freckles/moles), etc. - abnormal endogenous products
- result from inborn metabolic errors
- ex: abnormal glycogen metabolism, jaundice in babies (bilirubin destruction) - exogenous products
- environmental agents/pigments not broken down by the cell
what are pathologic calcifications
abnormal tissue deposition of calcium salts along with smaller amounts of iron, magnesium, and other minerals
can be either dystrophic or metastatic
what is the difference between dystrophic calcification and metastatic calcification?
dystrophic occurs in dead or dying tissue
-ex: in CAD, too much LDL forms plaques in the arteries
- can also result from prolonged ischemia (significantly reduced blood flow)
metastatic calcification occurs in normal tissue
- ex: too much blood calcium –> padgett’s disease
what are the 5 causes of cell injury
- injury from physical agents
- radiation injury
- chemical injury
- injury from biologic agents
- injury from nutritional imbalances
examples of cell injury from physical agents
mechanical forces
temperature extremes
electrical forces
examples of cell injury from radiation
ionizing radiation
ultraviolet radiation
non-ionizing radiation
examples of cell injury from chemicals
drugs
carbon tetrachloride (industrially used environmental substance)
lead toxicity (scant amounts in foods, chipped paint, old pipes –>water)
mercury
examples of cell injury from biological agents
viruses (implementation into DNA)
parasites
bacteria (very dangerous due to replication)
examples of cell injury from nutritional imbalances
excesses (ex:obesity) deficiencies (ex: irons and vitamins)
what are the 3 mechanisms of cell injury
- free radical formation
- hypoxia/ischemia–> ATP depletion
- disruption of intracellular calcium homeostasis (activates enzymes that are damaging to cells)
what is hypoxic cell injury and how is it caused?
hypoxic cell injury deprives cells of oxygen and interrupts oxidative metabolism (ATP generation)
the longer a tissue is hypoxic, the greater chance of irreversible cell injury
hypoxia can be caused by:
- inadequate amount of oxygen in the air
- respiratory disease
- inability of the cells to use oxygen
- edema
- ischemia (decreased oxygen/blood flow to the tissues)
do injured cells always die?
no, they can have:
reversible injuries that the cell can recover from
- occurs by cellular swelling (impairment of Na/K pump) or fatty change (intracellular fat accumulation)
apoptosis can occur (this process is programmed, cell fragments are engulfed by a phagocytic cell)
or the cells can start dying in the formation of necrosis
- cell death in an organ or tissues that are still part of a living person (not replaceable)
what is gangrene
the term for an accumulated mass of tissue that has undergone necrosis
can be dry (slowly shrinks, wrinkles, black) or wet (rapid change –> cold, swollen, pulseless, moist, bleb formation, foul smell)
