CELL INJURY DEFINITIONS

Question 1

reversible functional and morphological changes

Answer 1

Reversible cell injury

Question 2

cell cannot recover from injury resulting in cell death (necrosis or apoptosis)

Answer 2

Irreversible cell injury

Question 3

reduces aerobic respiration

Answer 3

Oxygen deprivation*

Question 4

mechanical trauma, extreme temperatures, sudden changes in atmospheric pressure, radiation and electric
shock

Answer 4

Physical agents

Question 5

glucose or salt in hypertonic concentrations (electrolyte imbalance), oxygen at toxic levels, poisons (arsenic, cyanide, etc.), environmental and air pollutants, insecticides/herbicides, recreational and therapeutic drugs

Answer 5

Chemical agents and drugs

Question 6

bacteria, fungi, parasites, viruses

Answer 6

Infectious agents

Question 7

injurious reactions to self-antigens (autoimmunity), inflammation

Answer 7

Immunologic reactions

Question 8

deficiency of functional proteins (enzyme defects, accumulation of damaged DNA or misfolded proteins)

Answer 8

Genetic derangements

Question 9

vitamin or protein-calorie deficiency, excess cholesterol

Answer 9

Nutritional imbalances

Question 10

blebbing, blunting and loss of microvilli

Answer 10

Plasma membrane alterations

Question 11

swelling and appearance of small amphorous densities

Answer 11

Mitochondrial changes

Question 12

clumping of nuclear

chromatin, disaggregation of granular and fibrillar elements

Answer 12

Nuclear alterations

Question 13

ER swelling, cellular swelling, loss of microvilli, blebs

Answer 13

Failed Na+ pumps

Question 14

decreased glycogen, lactic acid production → acidosis

Answer 14

Increased glycolysis

Question 15

influx of Ca2+ decreasing phospholipids in membrane

Answer 15

Failure of Ca2+ pumps

Question 16

structural disruption of protein synthesis and lipid deposition

Answer 16

Depletion of ATP

Question 17

occur during normal metabolic processes (mitochondrial

respiration and energy generation)

Answer 17

Reduction-oxidation (redox) reactions

Question 18

weapons for destroying microbes and other substances

Answer 18

Produced in phagocytic leukocytes

Question 19

vasodilator (important chemical mediator and part of inflammatory response), can act as free radical and be converted to highly reactive ONOO-

Answer 19

Nitric oxide

Question 20

condition where there are increased amounts of free radicals

Answer 20

Oxidative stress

Question 21

ischemia and certain toxins cause influx of cytosolic calcium

Answer 21

Loss of calcium homeostasis

Question 22

decreased ATP

Answer 22

ATPase

Question 23

decreased phospholipids

Answer 23

Phospholipase

Question 24

disrupt cell membrane and cytoskeletal proteins

Answer 24

Proteases

Question 25

damage nuclear chromatin

Answer 25

Endonucleases

Question 26

(↓ phospholipid synthesis, ↑ phospholipid breakdown) - contents leak into the
membrane

Answer 26

Defects in membrane permeability

Question 27

sensitive to many types of injurious stimuli (increased cytosolic Ca2+, ROS, oxygen deprivation, etc.), results in biochemical abnormalities

Answer 27

Mitochondrial damage and dysfunction

Question 28

formation of reactive oxygen species (free radicals)

Answer 28

Abnormal oxidative phosphorylation

Question 29

ischemia tends to cause more rapid and severe cell and tissue injury than does
hypoxia in the absence of ischemia because aerobic and anaerobic respiration compromised

Answer 29

Reversible ischemia (may become irreversible)

Question 30

cells proceed to die after blood flow restored; injury is paradoxically exacerbated and proceeds at an accelerated pace

• as a consequence, reperfused tissues may sustain loss of cells in addition to the cells that are
  irreversibly damaged at the end of ischemia (contributes to tissue damage during myocardial and cerebral infarction and following therapies to restore blood flow
• ex. myocardial infarction, stroke, organ transplantation)

Answer 30

Ischemic/reperfusion injury

Question 31

major limitation to drug therapy, liver frequent target of drug toxicity

Answer 31

Chemical (Toxic) Injury

Question 32

some chemicals injure cells directly by combining with critical molecular components

Answer 32

Direct acting chemicals

Question 33

most toxic chemicals are not biologically active in their native form but convert to
reactive toxic metabolites which then act on target molecules

Answer 33

Convert to toxic metabolites

Question 34

a single unpaired electron in an outer orbital making it

HIGHLY REACTIVE and UNSTABLE

Answer 34

Free radicals

Question 35

energy knocks electrons to outer orbitals

Answer 35

Radiation

Question 36

ex. normal respiration

Answer 36

Endogenous redox reactions

Question 37

iron (hemoglobin), copper; donate or accept electrons during intracellular reactions and catalyze
free radical formation

(ex. Fenton reaction)

Answer 37

Transition metals

Question 38

important chemical mediator (vasodilator)

Answer 38

Nitric oxide

Question 39

unsaturated fatty acids of membrane lipids attacked by O2-

Answer 39

Lipid peroxidation of membranes

Question 40

free radicals promote oxidation of AA side chains, formation of cross-linkages,
and polypeptide fragmentation;
disrupts conformation of structural proteins enhancing proteosomal degradation of
unfolded and misfolded proteins

Answer 40

Oxidative modifications of proteins

Question 41

free radicals cause single and double-stranded breaks in DNA, cross-linking of DNA strands and formation of adducts

(ex. cellular aging)

Answer 41

DNA fragmentation

Question 42

endogenous (self-produced), exogenous (supplements); block initiation of free radical formation and inactivate (scavenge) free radicals

Answer 42

Antioxidants

Question 43

inherently unstable and spontaneously decay

Answer 43

Spontaneous decay

Question 44

catalase, superoxide dismutases, glutathione peroxidase

Answer 44

Free radical scavenging enzymes

Question 45

materials from external environment taken up and degraded

Answer 45

Heterophagy

Question 46

degeneration of intracellular organelles

*Common phenomenon involved in removal of damaged or senescent organelles

Answer 46

Autophagy