Cell Adaptation & Injury (L2) Flashcards
Define hypertrophy
Increase in cell size and function.
Define hyperplasia.
Increase in the number of cells.
Atrophy
Decrease in cell size and function
Metaplasia
Change from a specialized cell type to less specialized one or to one that is needed to allow it to stabilize and injury.
True or false? Hypertrophy and hyperplasia cannot occur simultaneously in tissues.
False. They CAN occur simultaneously as cells adapt to a stress or increased workload.
Define atrophy. What are its causes?
Decrease in size and function of cells. Causes: -deficient nutrients -decreased workload -lack of stimulus (disuse, enervation, loss of hormone) -increased pressure -senility -drugs: corticosteroids
True or false? Atrophied cells are no longer living.
False! Atrophied cells are still alive with reduced function.
Atrophied cells have a ________ in protein synthesis, _________ in protein degradation, __________ in autophagy process and autophagic vacuoles within atrophied cells.
Atrophied cells have a DECREASE in protein synthesis, INCREASE in protein degradation, INCREASE in authophagy process and autophagic vacuoles within atrophied cells.
True or false? During metaplasia, the original cells are modified genetically.
False. The original cells are NOT modified genetically; stem cells are reprogrammed.
(Ex: ooseous metaplasia) age related lesion
What process is considered “new growth” that is poorly controlled. Process where cells undergo genetic changes uncontrollably.
Neoplasia
What process involves resulting cells are normal appearing, have normal genes, and growth is still controlled by normal processes.
Metaplasia
Cell injury results when ______ has been exceeded
Adaptation
5 factors that determine whether an injury is reversible or irreversible.
- type of cell
- type of injury
- severity
- duration
- multiplicity of injurious agents
There are 9 causes of cell injury. Name 5.
- oxygen deprivation
- overwork
- aging
- genetic changes
- infectious agents
Acute cellular swelling which is REVERSIBLE cell injury (hydropic degeneration) occurs when?
When the normal cell membrane homeostasis is disrupted from the loss of normal function of sodium/potassium pump.
- reduced oxygen tension
- direct membrane damage
- reduced ATP availability
Necrosis is _____ cell death.
Apoptosis is _____ cell death.
Necrosis is accidental cell death. Apoptosis is programmed cell death.
During necrosis, the nucleus changes as follow. What are the pathological names for each of the following?
- Shrink and condense
- Break into components
- Fade away (dissolve)
- Pyknosis
- Karyorrhexis
- Karyolysis
In what 3 scenarios does apoptosis occur?
- DNA damage
- Accumulation of misfolded proteins
- Cell death in viral infections
What are the two pathways that apoptosis is activated by?
- intrinsic (mitochondrial)
- extrinsic (death receptor)
What is the intrinsic mechanism of apoptosis?
-cell injury or loss of growth factors causes release of cytochrome C from mitochondria and activation of caspase cascade.
Describe the extrinsic mechanism of apoptosis.
-external stimulus interacts w/ the “death receptor” activating a different caspase cascade.
What is the caspase cascade?
Initiator caspases activated through intrinsic or extrinsic mechanism
What to executioner caspases do?
Activate endonuclease that fragments DNA and protease breaks down cytoskeleton.
- cells shrink, nucleus condenses and DNA fragments
- cytoplasmic organelles remain intact
- cytoplasm blebs
- blebs break off and contain normal organelles and nuclear fragments (apoptotic bodies)
- apoptotic bodies phagocytized by local macrophages, fails to stimulate inflammation
True or false? Apoptosis usually does not produce gross changes in tissues.
True
