Cell injury and death Flashcards
living cell must maintain its function in order to a be able to produce energy (function)
> changes in environment can stress the cell
> the cell must be able to adapt in order to survive (temperature changes, toxins )
> cell injury can be reversible - allows cell to recover
> or if injury exceeds cells capacity to adapt cell dies
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Types of cell injury (2)
Depends on extent of injury (intensity duration)
1) sublethal or reversible
2) irreversible injury with cell destruction/ death
It impairs cell function but does not cause cell to die
> two patterns are observable:
Cellular swelling, intracelluar accumulation
Reversible cell injury
Cellular swelling
Occurs as a result of of hypoxic cell injury (lack of oxygen) ishemia, virus, bacteria, extreme heat cold
Intracellular accumulation (2)
1) fatty acids linked to intravenous are accumulation of fat. It’s reversible but indicates severe injury (ex. Liver, kidneys, heart; also atrophy, hypertrophy, hyperplasia, metaplasia, dysplasia)
2) endogenous, exogenous sources: glycogen, bilirubin, coal dust silica (accumulated substances)
> apoptosis or programmed cell death
> necrosis or cell death
Irreversible cell injury
Programmed cell death or Apoptosis
Disintegration of cells into membrane-bound particles that are then phagocytosed by other cells
During Apoptosis is a highly selective process that controls tissue regeneneration
Eliminates aged and damage cells…
Responsible for many physiological processes:
Programmed cell destruction during embryonic development
Hormone dependent involuted of tissues
Death o immune cells
apoptosis
Linked to many pathological processes and disease:
Contributes in carcinogenesis
Cell death associated with viral infections, such as hepatitis B,C
Implicated in neurodegenerative disorders such as Alzeimers, Parkinson’s (not enough dopamine produced) and ALS (death of brain tissue)
apoptosis
Refers to cell death
Necrosis
Differs from Apoptosis
Unregulated enzymatic digestion of cell components
Loss of cell membrane integrity
Initiation of inflammatory response
Interference with cell replacement and tissue regeneration
Necrosis
Presented in different forms: coagulative (ishemia, viruses, toxin) liquefaction ——- ( as result of bacterial infections), caseous —–(TB) and gangrene (deficient/ absent blood supply
Necrosis
Gangrene occurs when a considerable mass of tissue undergoes necrosis
It can present itself in 3 ways
1) dry (confined almost exclusively to extremities-arteries)
2) wet (veins flow impaired and bacteria)
3) gas ( result from infection of devitalized tissue caused by clostridium bacteria.
Cellular aging
Aging is the press that involves the cells and tissues of the body
Causes of aging are explained by a number of theories
