A.pathology Exam-cell injury

Question 1

What is necrosis/oncosis?

Answer 1

Cell death due to swelling, cell fragmentation, cytoplasmic protein denaturation, fragmentation of cell organelles

Question 2

What is apoptosis?

Answer 2

Cell death due to shrinkage, decrease in size, condensation and fragmentation of chromatin

Question 3

What can be the cell response to injury?

Answer 3

• Reversible injury

- Cell death

Question 4

What are the ways cell injury can be classified?

Answer 4

• extrinsic= physical trauma, virus, toxins…
• intrinsic= spontaneous genetic mutations
• mixed= workload, nutritional, immunological

Question 5

What are the general mechanisms of cell injury?

Answer 5

• ATP depletion=hypoxia
• membrane damage= multiple causes (free radicals)
• disturbances of cellular metabolism & genetic damage

Question 6

How does cells respond to injury/stress?

Answer 6

• adaptation
• degeneration or intra/extracellular ackumulations
• death

Question 7

What are specific causes of cell injury?

Answer 7

• oxygen deficiency
• physical agents
• infectious agents
• nutritional deficiencies, imbalances
• genetic derangement
• workload imbalance
• chemicals, toxins, drugs
• immunologic dysfunctions
• aging

Question 8

Cell injury due to Oxygen deficiency

Answer 8

• Most common+important cause

- most sensitive cells= neurons, hepatocytes, cardiac myocytes, renal tubule cells

Question 9

Cell injury due to physical agents

Answer 9

• mechanical trauma
• extreme temperatures (protein/enzyme denaturation)
• sudden changes in atmospheric pressure
• radiation

Question 10

Cell injury due to infectious agents

Answer 10

• virus
• bacteria
• parasites

Question 11

Cell injury du to nutritional deficiencies, imbalances

Answer 11

• protein to calorie deficiencies
• calorie excess
• vitamin/mineral imbalances

Question 12

Cell injury due to workload imbalances?

Answer 12

• overworked cells may adapt to demand, or die

- lack of stimuli may shrink, and die= atrophy

Question 13

Cell injury due to chemicals, drugs, toxins

Answer 13

• block or stimulate membrane receptors
• alter specific enzyme systems
• produce toxic free radicals
• alter cell permeability
• damage chromosomes
• modify metabolic pathways
• damage structural components of the cell

Question 14

Cell injury due to immunologic dysfubction

Answer 14

• immunodeficiency=lack of response
• autoimmune disease=against own cells
• hypersensitivity reactions=exaggerated response

Question 15

What is acute swelling/hydronic degeneration?

Answer 15

-most common+fundamental expression of cell injury
-result of water overload due to failure of maintaining homeostasis
Changes begin with increased uptake of water

Question 16

Ischemia in cell injury

Answer 16

1. Reduced oxidative phosphorylation
2. Decreased ATP synthesis
   - decreased Na+/K+ pump action=influx of Ca2+, Na+, H2O, efflux of K+= ER swelling, cellular swelling, loss of microvili, myelin figures
   - increased anaerobic glycolysis=low glycogen, low pH, increased lactic acid= clumping of nuclear chromatin
   - detachment of ribosomes=reduced protein synthesis=lipid deposition

Question 17

Cell membrane injury

Answer 17

• destruction of selective permeability barrier
• result of chemical modification of phospholipids
• affected cells quickly lysed by water overload

Question 18

What is the morphology of Morphology of acute cell swelling?

Answer 18

Gross:
-pallor, organ swelling, decreased gravity, parenchyma bulge when incised
Microscopic:
-dilated organelles, vacuolar degeneration, ballooning degeneration (infection of epitheliotropic virus)