Mechanism of Cell Injury

Question 1

4 intracellular systems are particularly vulnerable to injury

Answer 1

° cell membrane
° mitochondria
° protein synthesis
° genetic apparatus

Question 2

are common consequences of both ischemic and toxic injury

Answer 2

ATP depletion and ATP synthesis

Question 3

Cell Membranes

Answer 3

especially ionic/osmotic homeostasis

Question 4

mitochondria

Answer 4

oxidation phosphorylation/ATP production

Question 5

Protein synthesis, folding and packaging

Answer 5

Structural and functional proteins

Question 6

genetic apparatus

Answer 6

DNA/RNA

Question 7

ATP required;

Answer 7

✓membrane transport
✓protein synthesis
✓protein stability
✓lipogenesis

Question 8

are chemical species with a single unpaired electron in outer orbit readily react with organic or inorganic chemicals, avidly attack/degrade membranes, proteins and nuclei acids

Answer 8

free radicals

Question 9

free radical-induced injury, particularly that induced by activated oxygen species, is an important mechanism of cell damage in many disease processes, what are these?

Answer 9

chemical, radiation, O2 toxicity, inflammation, reperfusion

Question 10

it occurs when the free radical generation overwhelms antioxidant defense mechanism

Answer 10

cell injury

Question 11

Generation of free radicals

Answer 11

✓ cellular metabolism
✓ enzymatic metabolism of exogenous chemicals
✓ ionizing radiation
✓ divalent metals

Question 12

small amounts produced from cell detox (loss of electrons) reactions

Answer 12

cellular metabolism

Question 13

some intermediary metabolites of chemical/drugs are highly reactive free radicals

Answer 13

enzymatic metabolism of exogenous chemicals

Question 14

hydrolyzes water into hydroxyl and hydrogen free radicals

Answer 14

ionizing radiation

Question 15

the transition metals, accept or donate free electrons during certain intracellular reactions

Answer 15

divalent metals

Question 16

important reactants

Answer 16

✓ superoxide anion (O2) hydroxyl radical (OH), hydrogen peroxide (H2O2) and peroxynitrite (ONOO)
✓ H2O2
✓ ferric (Fe3+)

Question 17

not a free radical. is a frequent by-product of oxidative metabolism that can generate hydroxyl radicals from reactions with copper or ferrous ions

Answer 17

H2O2

Question 18

main sites of damage

Answer 18

✓ damage of membranes (lipid peroxidation)
✓ damage of proteins
✓ damage to DNA

Question 19

Protective mechanism of the Cell

Answer 19

✓ storage and transport proteins
✓ antioxidants
✓ enzyme that involve in neutralizing free radicals

Question 20

biochemical mechanism

Answer 20

✓ ATP depletion
✓ Free radical induced injury
✓ intracellular calcium and loss of calcium homeostasis
✓ mitochondrial damage
✓ defects in membrane permeability

Question 21

can catalyze formation of reactive oxygen forms

Answer 21

iron and copper

Question 22

Mechanisms of cell injury

Answer 22

✓ general consideration
✓ biochemical mechanisms
✓ chemical (toxic) injury

Question 23

all cells are depending on oxidative metabolism for long term survival

Answer 23

mitochondrial damage

Question 24

catalyzes that breaks down H2O2 to O2+H2O

Answer 24

catalase

Question 25

catalyzes the conversion of O2 to H2O2

Answer 25

superoxide dismutase (SOD)

Question 26

defects in membrane permeability

Answer 26

✓ damage to membranes often critical
✓ indirect damage
✓ direct damage

Question 27

chemicals and certain drugs/toxins produce damage in one of two ways

Answer 27

✓ direct interaction
✓ conversion to reactive toxic metabolites

Question 28

in humans and dogs, it is detoxified in liver to glucuronide and sulfate conjugates

Answer 28

acetaminophen (tylenol) toxicity

Question 29

binds to molecules in hepatocytes and causes necrosis

Answer 29

electrophilic

Question 30

it released from the liver cells and results in oxidative damage to hemoglobin

Answer 30

para-aminophenol

Question 31

is highly reactive and causes lipid peroxidation (autocatyzing)

Answer 31

CCl3