[C] 1.16 Degenerative changes of cells and tissues

Question 1

Cell injury was defined by…

Answer 1

Rudolf Virchow

Question 2

Mechanisms of cell injury: General considerations

Answer 2

• Cellular response depends on:
  
  • Type, duration, severity of harm
• Consequences depend on:
  
  • Type, condition, adaptability of the cell

Question 3

Cellular injury results from functional, and biochemical abnormalities in one or more of which essential cell components?

Answer 3

• Oxidative phosphorylation (ATP)
• Membrane integrity
• Protein synthesis
• Cytoskeleton
• DNA integrity

Question 4

ATP synthesis as a mechanism of cell injury: Steps

Answer 4

1. ATP decrease
2. Rise in IC Ca²⁺
3. Mitochondrial damage
4. ROS levels rising
5. Membrane permeability defects

Question 5

ATP decrease as a mechanism of cell injury

Answer 5

1. ↓ Na⁺/K⁺ ATPase pump activity
2. IC [Na⁺] rise → Water influx → Cell swelling

or

1. Anaerobic glycolysis: Glycogen depletes
2. ↑ Lactic acid → ↓ pH
3. ↓ Enzyme activity

or

1. ↓ Ca²⁺,Mg²⁺ ATPase pump activity

Question 6

Rise in IC Ca²⁺ as a mechanism of cell injury

Answer 6

Enzyme activation:

• ATPases:
  
  • Phospholipases
  • Proteases
  • Proteases
  • Endonucleases
  • Mitochondrion degeneration

Question 7

Mitochondrial damage

Answer 7

1. ↑ Ca²⁺, phospholipases, ROS
2. Cytochrome C leakage
3. Apoptosis

Question 8

ROS levels rising (free radicals)

Answer 8

1. Lipidperoxidation of the membranes
2. Oxidative damage of proteins
3. DNS damage

• Antioxidant systems:
  
  • Glutathione peroxidase, superoxide dismutase, vitamin E, C

Question 9

Membrane permeability defects

Answer 9

1. Mitochondrial damage
2. ER-damage → Damaged protein synthesis
3. Cytoskeletal abnormalities
4. Leakage of lysosomal enzymes

Question 10

Title the figure

Answer 10

The effect of injury on cell injury

Question 11

Reperfusion injury

Answer 11

Restoration of blood flow after ischaemia → Severe cell damage

Question 12

Give the effects of reperfusion injury

Answer 12

• Large oxygen influs, ROS
• Mitochondrial damage
• Compromised antioxidant system
• Inflammation → Adhesion molecules expressed
  
  • These recruit neutrophils from restored blood flow
• Complement pathway

Question 13

Degenerative cell and tissue damage cause

Answer 13

Altered function

Question 14

Altered cell function as a cause of degenerative cell and tissue damage

Answer 14

Not always visible

• Detectable changes are needed
  
  • Deposition of certain materials
  • Enzymatic changes
  • Decreased function, metabolism
• Most severe outcome: Cell death

Question 15

Degenerative/regressive changes of cells

Answer 15

• Degeneration → Regressive changes
• Metabolic disorders
  
  • Water metabolism
  • Fat
  • Protein
  • Mineral salts
  • Accumulation/deposition of different materials

Question 16

Forms of degeneration

Answer 16

• Acquired - Congenital
• Results from enzyme defects
  
  • Incomplete decomposition of a material
  • Same end product
  • Different end product
  • Accumulation of intermediate metabolites
    
    • Thesaurismosis

Question 17

Intracellular changes

Answer 17

• Damage of the cell organelles
  
  • ER, mitochondrion
• Deposition or accumulation
• Depletion
• Nuclear damage
• Cell death

Question 18

Damage of the cell organelles

Answer 18

• Membrane lined organelles
• The membrane tears up
  
  • Enzyme leakage
  • SER dilation
  • Circumscribed necrosis

Question 19

Nuclear changes

Answer 19

• Nuclear membrane hyperchromatosis
• Karyopycnosis
• Karyorhexis
• Karyolysis

Question 20

Regressive tissue changes

Answer 20

• Cell degeneration
• Degeneration of the ECM
  
  • Deposition
  • Accumulation
  • Depletion of different molecules
  • Damage of the terminal blood system

Question 21

Regressive changes in the organs

Answer 21

• Cell degeneration +
• ECM degeneration +
• Fibrovascular system degeneration
  
  • Not only the blood circulation
• Atrophy