Cell Injury and Cell Death (parts 1 & 2)

Question 1

Distinguish reversible from irreversible cell injury.

Answer 1

Reversible Injury means cell can be restored to normal phenotype and function
Irreversible injury means cell cannot be restored to its normal phenotype, it is permanently altered

Question 2

Identify the cytological changes that are associated with irreversible injury.

Answer 2

• Mitochondrial change (porous)

Question 3

Explain how Steatosis occurs due to alcohol ingestion.

Answer 3

• Alcohol converted to acetate in the liver
• Oxidative stress produces NADH
o Liver synthesizes more triglyceride
o Decreased lipoprotein synthesis
o Decreased transportation and secretion of VLDL
o Detect excess fat with oil red stain
• Microsomal system that manages toxins is also activated

Question 4

Name and distinguish 4 types of pathological necrosis.

Answer 4

• Liquefactive Necrosis: Abscesses and acute inflammation associated (leuockytes that accumulate = pus)
• Gangrenous necrosis: Ischemic injury following bacterial colonization, usually coagulative necrosis but can be liquifactive if bacteria are around
• Caseous Necrosis: Cottage cheese like infection, granuloma formation
• Fat necrosis: Fat destruction usually pancreatic lipases
• Coagulative necrosis: Original cell structure remains because cell injury destroys degenerative enzymes

Question 5

Explain the relationship between hemochromatosis and cirrhosis.

Answer 5

• Hemochromatosis: Genetic disorder that results in the accumulation of iron in the blood
• Cirrhosis: Untreated hemochromatosis results in fibrous tissue, nodular liver, hepatocellular carcinoma

Question 6

Diagram the mechanisms active in cellular apoptosis.

Answer 6

•	Intrinsic Pathway
    -	BCL-2 regulated
    -	Bax-Bak activation is lost
    -	Cytochrome C is released
    -	Caspase activation
•	Extrinsic Pathway
    -	Activate death receptors TNF or FAS receptors

Question 7

Name four features of cellular injury that are reversible.

Answer 7

• Swelling
• Fatty change
• Plasma membrane alterations
• ER dilation
• Increased Eosinophilic staining

Question 8

Describe the electrolyte shifts that occur in ischemic cell injury leading to cell death.

Answer 8

• Loss of oxidative phosphorylation = loss of ATP and import of Na and Ca

Question 9

Explain the role of Ca++ ions in irreversible cell injury.

Answer 9

•	Calcium precipitation in mitochondria
    o	Depletion of ATP
    o	Oxidative stress
    o	Defects in membrane permeability
    o	Damage to DNA\proteins