Chapter 2- Cellular Responses To Stress Flashcards
What is etiology?
The cause of a disease or an initiating event
What is pathogenesis?
The mechanism of disease development
What is morphological change?
Structural alterations in cells/tissues due to the disease
What is clinical significance?
The functional consequences of the morphological change
What are some possible causes of cell injury?
Hypoxia Physical agents Infectious agents Immunologic reactions Genetic derangements Nutritional imbalances
What is adaptation?
Cellular stressors induce a new state causing changes but the cells remain viable
What is hypertrophy?
Increased cell size
Increased cell protein production
What is hyperplasia?
Increased number of cells
What are the different types of hyperplasia and their causes?
Physiologic- hormones or GFs
Pathologic- inappropriate growth
Compensatory- after resection (eg. liver)
What is atrophy?
Decreased number or cells and size of cells
What is metaplasia?
One cell type is replaced by another
What is the difference between a reversible and irreversible injury?
Reversible- changes can be restored if the stimulus is removed
Irreversible- stressor exceeds the cell’s adaptive capacity
What are two morphological changes associated with reversible injuries?
- Cellular swelling due to hypoxia
2. Fatty changes
What are the different causes/types of intracellular accumulations?
Inadequate removal of normal substances (transport)
Abnormal endogenous substances (folding)
Defects in metabolism
Abnormal exogenous substances
Steatosis/fatty change (triglyceride accumulation)
Proteins (excess, misfolding, defective transport)
Hyaline change
Glycogen (metabolism abnormality)
Pigments
What are the different types of necrosis?
Coagulative Liquefactive Gangrenous Caseous Fat Fibrinoid
What are the characteristics of coagulative necrosis?
Cell and tissue framework preserved
Cells are eventually phagocytosed and dissolved by inflammatory cells
What type of necrosis is associated with hypoxia cell death?
Coagulative
What are the characteristics of liquefactive necrosis?
Autolysis and heterolysis predominate over protein denaturation
Where is liquefactive necrosis commonly seen?
The brain
What is gangrenous necrosis associated with?
Bacterial infection with coagulative necrosis
What are the two types of gangrenous necrosis?
- Wet
2. Gas (clostridium)
What infection is caseous necrosis associated with?
Tb
What causes the morphology of fat necrosis?
Lipase releases fatty acids which complex with calcium to form soap
What causes fibrinoid necrosis?
Immune complexes deposited in blood vessels cause inflammation and fibrosis
What are the differences between apoptosis and necrosis?
Apoptosis- organized/programmes cell death, components released in vesicles (PM intact), no inflammation
Necrosis- PM damage results in the leakage of intracellular enzymes, causing an inflammatory response
What are the three things that happen to genetic material during necrosis?
- Karyolysis- DNA degradation
- Pyknosis- nuclear shrinkage
- Karyorrhexis- nucleus is fragmented
What are the two pathways of apoptosis and the mechanisms by which they occur?
Intrinsic/mitochondrial- BCL2 proteins activated due to cell injury (mitochondrial leakage), caspase activation
Death receptor- Fas ligand, death receptor complex activates caspases
How do caspases exert their effects?
Act of DNase inhibitor, resulting in fragmentation
What are some examples of things that lead to apoptosis?
GF deprivation
DNA damage (p53 accumulation stops cycle at G1)
Protein misfolding (unfolded protein response can activate caspases)
TNF family receptors- Fas interactions remove self recognizing lymphs
Cytotoxic lymphs- recognize foreign Ag and secrete porforin
What are the most common clinical injuries?
Hypoxia and ischemia
What is ischemia-reperfusion injury?
Restoration of blood flow increased cell injury and potentially causes cell death
How does ischemia-reperfusion injury occur?
Oxidative stress (free radical accumulation)
Intracellular calcium overload
Inflammation (more cells)
Complement activation (IgM deposition)
What is the difference between direct and indirect toxicity?
Direct- chemical directly damages cells
Indirect- chemical is converted to a toxic metabolite that damages cells
What is pathologic calcification?
Abnormal tissue deposition of calcium salts
What are the two types of pathologic calcification?
- Dystrophic- in areas of necrosis (eg. atherosclerosis)
2. Metastatic- hypercalcemia causes deposition in normal tissue
What can cause metastatic pathologic calcification?
Elevated PTH
Bone destruction
Vitamin D intoxication
Renal failure (secondary hyperparathyroidism)
What is cellular senescence?
Limited capacity for replication
Accumulated metabolic and genetic damage
