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Pathology chapter 01


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Define hyperplasia
Increased cell number
Define hypertrophy
Increased cell mass
Define atrophy
Decreased cell mass
Define metaplasia
Change from one mature cell type to another
Define reversible injury
Denotes pathologic cell changes that can be restored to normalcy if the stimulus is removed or if the cause of injury is mild
Define irreversible injury
Occurs when stressors exceed the capacity of the cell to adapt (beyond a point of no return) and denotes permanent pathologic changes that cause cell death
Define necrosis
The more common type of cell death, involving severe cell swelling, denaturation and coagulation of proteins, breakdown of cellular organelles, and cell rupture. Usually, a large number of cells in the adjoining tissue are affected
Necrosis always represents a pathologic process
Define apoptosis
Occurs when a cell dies by activation of an internal suicide program, involving and orchestrated disassembly of cellular components; there is minimal disruption of the surrounding tissue.
What causes oxygen deprivation?
1. Ischemia (loss of blood supply).
2. Inadequate oxygenation (eg cardiorespiratory failure).
3. Loss of oxygen-carrying capacity of the blood (eg anemia, carbon monoxide poisoning)
Responses to injurious stimuli depend on:
Type of injury, its duration, and its severity
Consequences of injury depend on:
Type, State, and Adaptability of the injured cell
Cell injury results from abnormalities in one or more of these five cellular components:
1. Aerobic respiration, involving mitochondrial oxidative phosphorylation and ATP production
2.Integrity of the genetic apparatus
3. Protein synthesis
4.Intracellular cytoskeleton
5.Maintenace of cell membrane integrity
The intracellular mechanisms of cell injury fall into one of these five general pathways:
1. ATP depletion
2. Mitochondrial damage
3. Influx of intracellular calcium and loss of calcium homeostasis
4. Accumulation of Oxygen-derived radicals
5. Defects in membrane permeability
Damaged mitochondria form a high-conductance channel called:
Mitochondrial permeability transition (MPT)
What two phenomena consistenty characterize irreversible injury?
1. Inability to reverse mitochondrial dysfunction.
2. Development of profound disturbances in membrane function
Name two morphological characteristics of reversible injury
Cell swelling and Fatty change
What two processes underlie the basic morphologic changes in necrosis
Denaturation of proteins and enzymatic digestion of organelles and other cytosolic components
Define coagulative necrosis
Most common pattern, predominated by protein denaturation with presevation of the cell and tissue framework. Characteristic of hypoxic death
Define liquefactive necrosis
Occurs when autolysis or heterolysis predominates over protein denaturation. Necrotic area is soft and filled with fluid
Define caseous necrosis
Characteristic of tuberculous lesions. Apperas forssly as soft, friable,cheesy material and microscopically as amorphous eosinophilic material with cell debris
Define fat necrosis
Seen in adipose tissue. Lipase activation releases fatty acids from triglycerides, which then complex with calcium to create soaps.

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