Chapter 3: Cellular Adaptation, Injury, and Death

Question 1

Learning Objectives

Answer 1

1. Cite the general purpose of changes in cell structure and function that occur as the result of normal adaptive processes.
2. Describe cell changes that occur with atrophy, hypertrophy, hyperplasia, metaplasia, and dysplasia, and state general conditions under which the changes occur.
3. Compare the pathogenesis and effects of dystrophic and metastatic calcifications.
4. Relate free radical formation and oxidative stress to cell injury and death.
5. Differentiate cell death by apoptosis versus necrosis and gangrene.

Question 2

In what ways do cells adapt to their environment (3)

Answer 2

1. size (atrophy and hypertrophy)
2. number (hyperplasia)
3. form (metaplasia & dysplasia)

Question 3

Atrophy v Hypertrophy

Answer 3

cell adaptation where a cell can either shrink or grow in size

Question 4

hyperplasia

Answer 4

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

Question 5

metaplasia v dysplasia

Answer 5

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

Question 6

what are the different types of intracellular accumulations

Answer 6

1. normal bodily substances
   - lipids, proteins, carbs, melanin (freckles/moles), etc.
2. abnormal endogenous products
   - result from inborn metabolic errors
   - ex: abnormal glycogen metabolism, jaundice in babies (bilirubin destruction)
3. exogenous products
   - environmental agents/pigments not broken down by the cell

Question 7

what are pathologic calcifications

Answer 7

abnormal tissue deposition of calcium salts along with smaller amounts of iron, magnesium, and other minerals

can be either dystrophic or metastatic

Question 8

what is the difference between dystrophic calcification and metastatic calcification?

Answer 8

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

Question 9

what are the 5 causes of cell injury

Answer 9

1. injury from physical agents
2. radiation injury
3. chemical injury
4. injury from biologic agents
5. injury from nutritional imbalances

Question 10

examples of cell injury from physical agents

Answer 10

mechanical forces
temperature extremes
electrical forces

Question 11

examples of cell injury from radiation

Answer 11

ionizing radiation

ultraviolet radiation

non-ionizing radiation

Question 12

examples of cell injury from chemicals

Answer 12

drugs
carbon tetrachloride (industrially used environmental substance)
lead toxicity (scant amounts in foods, chipped paint, old pipes –>water)
mercury

Question 13

examples of cell injury from biological agents

Answer 13

viruses (implementation into DNA)
parasites
bacteria (very dangerous due to replication)

Question 14

examples of cell injury from nutritional imbalances

Answer 14

excesses (ex:obesity) deficiencies (ex: irons and vitamins)

Question 15

what are the 3 mechanisms of cell injury

Answer 15

1. free radical formation
2. hypoxia/ischemia–> ATP depletion
3. disruption of intracellular calcium homeostasis (activates enzymes that are damaging to cells)

Question 16

what is hypoxic cell injury and how is it caused?

Answer 16

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)

Question 17

do injured cells always die?

Answer 17

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)

Question 18

what is gangrene

Answer 18

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)