Cell Injury

Question 1

injury to a cell can disrupt…

Answer 1

• the chemical processes of a cel

- directly damage components of the cell

Question 2

8 categories of cell injury

Answer 2

1 hypoxia
2 chemical
3 physical
4 biological (infectious disease)
5 Immunologic
6 genetic
7 nutritional
8 aging (degenerative)

Question 3

living cells change in _____ and _____ when stressed/injured. These changes are clinically apparent as ______

Answer 3

1 structure and
2 function
3 symptoms

Question 4

an inability to ____ leads to cell injury

Answer 4

adapt

Question 5

irreversible injury can result in _____ or _____

Answer 5

necrosis or apoptosis

Question 6

adaptation

Answer 6

process by which cells change in size, number, and appearance in response to changes in cell environment.
-Changes can be physiologic or pathologic

Question 7

hyperplasia

Answer 7

increase in the number of cells - can be physiologic or pathologic

Question 8

hypertrophy

Answer 8

increase in the size of a cell because of increased cellular substance
-can be physio or patho

Question 9

atrophy

Answer 9

decrease in the size of a cell because of loss of cellular substance
-can be patho or physio

Question 10

metaplasia

Answer 10

substitution of one type of an adult cell for another type of adult cell
- always pathologic

Question 11

timeline of cell injury

Answer 11

1) reversible cell injury has a continuous decline in cell function until you get
2) cell death in which case it becomes irreversible cell injury
3) ultrastructural changes
4) light microscopic changes
5) gross morphological changes

Question 12

vulnerable biochemical systems to cell injury

Answer 12

• mitochondria
• cellular calcium
• integrity of membranes
• integrity of genetic material

Question 13

mitochondrial damage mechanism of cell injury

Answer 13

• decrease ATP has multiple downstream effects

- increase reactive oxygen species damages lipids, proteins and DNA

Question 14

Entry of calcium mechaism of cell injury

Answer 14

• increase mitochondrial permeability

- activation of multiple cellular enzymes

Question 15

mb damage mechanism of cell injury

Answer 15

• plasma mb= loss of cellular components

- lysosomal mb- enzymatic digestion of cellular components

Question 16

protein misfolding and DNA damage

Answer 16

activation of pro-apoptotic proteins

Question 17

hypoxic injury model causes

Answer 17

ischemia, hypoxemia, or decreased oxygen carrying capacity

Question 18

hypoxic injury model effects

Answer 18

• affects the mitochondria: decr oxidative p-lation and decr ATP causes…
  1) decr Na+ pump— influx of Ca2+, H2O, and Na+ and an efflux of K+ — ER swelling, cellular swelling, loss of microvilli, and blebs
  2) incr anaerobic glycolysis—- decr glycogen, incr lactic acid, decr pH — clumping of nuclear chromatin due to low pH
  3) Detachment of ribosomes– decr protein synthesis— lipid deposition

Question 19

Which enzymes does Ca activate?

Answer 19

1) phospholipase (decr phospholipids) and proteases (disrupt mb and cytoskeletal proteins) —- mb damage
2) endonuclease — nuclear damage
3) ATPase— decr ATP (also caused by incr mb permeability caused by Ca)

Question 20

altered mb permeability causes ______ to leak from cells which can be measured clinically

Answer 20

intracellular enzymes

Question 21

elevated CK or troponin

Answer 21

acute myocardial infarction

Question 22

elevated AST/ALT

Answer 22

hepatitis

Question 23

decreased ATP causes decreased intracellular oxygen which can be measured clinically via ___

Answer 23

lactic acid

Question 24

free radical

Answer 24

atom/s with a single unpaired electron in the outer orbit. They are chemically unstable and very reactive with components of the cell

Question 25

O2 superoxide removal

Answer 25

conversion to H2O2 by SOD

Question 26

H2O2 removal

Answer 26

decomposition to H2O by glutathione peroxidas and catalase

Question 27

pathologic effects of free radicals

Answer 27

- lipid peroxidase = mb damage - protein modifications = breakdown and misfolding - DNA damage= mutations

Question 28

Carbon tetrachloride

Answer 28

converted to CCl3 in hepatocytes and causes lipid peroxidation and damage to cell structures

Question 29

reperfusion injury

Answer 29

- return of blood/oxygen to ischemic tissue - oxygen derived free radicals produced - further injury to cells (can convert reversible injury to irreversible)

Question 30

morphology of REVERSIBLE cell injury chain of events

Answer 30

1. cellular swelling 2. steatosis (fatty change) 3. myelin figures 4. ER swelling (Na/K pumps = ineffective) 5. Membrane blebs

Question 31

hallmark of irreversible injury

Answer 31

- pyknosis = loss of nuclei - fragmentation of cells - leakage of contents

Question 32

pyknosis

Answer 32

cell damage causes loss of nuclei which look like little inkdots on H&E staining

Question 33

necrosis

Answer 33

- sum total of morphological changes that occur in living tissue following cell death (so not a disease but a process found in many diseases) - includes structural changes of nucleus and cytoplasm of dead cell - CHARACTERIZED BY the presence of leukocytes (especially neutrophils) infiltrating dead tissue from adjacent living tissue - morphological changes occur as a result of enzymatic breakdown of cell and denaturation of proteins

Question 34

coagulation necrosis

Answer 34

- pattern of necrosis associated with severe ischemia - in solid organs - histologically- ghost like remnants of intact cells which lack nuclei. the cell outline is preserved and the cytoplasm stains intense pink (eosinophilia) - macroscopically - tissue firm in early stages - ex. myocardial infarct, renal infarct

Question 35

liquefactive necrosis

Answer 35

-pattern of necrosis often associated with bacterial infections -microscopic- bacteria release enzymes causing a rapid loss of cellular structure and a collection of liquid and amorphous debris -macroscopic- creamy yellow material = abscess -IMPORTANT** pattern of necrosis with brain hypoxia/infarct -

Question 36

abscess

Answer 36

collection of neutrophils, dead cells, liquid

Question 37

caseous necrosis

Answer 37

- pattern of necrosis associated with an inflammatory reaction called granuloma - histologically - amorphous, granular debris (dead cells) i the center of granulomatous cell reaction - macrocopically - necrotic tissue is soft, white, friable

Question 38

enzymatic fat necrosis

Answer 38

focal cell death in the pancreas and adjacent fat | -when peripancreatic adipose tissue is broken down, free fatty acids and calcium result

Question 39

gangrene

Answer 39

coagulation necrosis of an extremity, bowel, or gallbladder

Question 40

wet gangrene

Answer 40

if bacteria contaminate dying tissue, superimposing liquefactive necrosis, the process is referred to as wet gangrene

Question 41

apoptosis

Answer 41

- regulated pattern of cell death characterized by nuclear condensation and fragmentation coupled with fragmentation of cytoplasm into apoptotic bodies - physiologic or pathologic - not associated with an inflammatory reaction - important distinction with necrosis - recognition, removal of dead cells by phagocytes - doesn't usually spill its contents - often includes single cells and not the whole tissue

Question 42

where is apoptosis seen?

Answer 42

- normal embryogenesis - hormone dependent physiological involution (menstrual cycle) - proliferating cell populations - DNA damage - infections - accumulation of misfolded proteins