Causes of cellular injury

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Causes of cellular injury

• 1. Hypoxia reduced oxygen supply.
• i. e. respiratory disease, cardiovascular
  diseases, loss of blood supply, loss of the
  oxygen-carrying capacity of the blood as in
  anemia or carbon monoxide poisoning.

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• 2. Physical agents
• Mechanical trauma, extremes of heat or cold,
  sudden changes in atmospheric pressure, radiant
  energy and electrical energy all have
  wide-ranging effects on cells.
• 3. Chemical agents
• Virtually any chemical agent or drug maybe
  implicated. Even an innocuous substance such as
  glucose, if sufficiently concentrated, may so
  derange the osmotic environment of the cell that
  it causes injury.

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• 4. Microbiologic agents
• A host of living agents, ranging in size from
  the submicroscopic viruses to grossly visible
  nematodes, may attack human causing cell injury.

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• 5. Abnormal immunological reactions
• The immune process is normally protective but
  in certain circumstances the reaction may become
  deranged. Hypersensitivity to various substances
  can lead to anaphylaxis or to more localized
  lesions such as asthma. In other circumstances
  the immune process may act against the body
  cellsautoimmunity.

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• 6. Genetic derangements
• Mutations may deprive the cell of a single
  enzyme or maybe so severe that they are
  incompatible with cell survival. The mutations
  may appear during gametogenesis, in the early
  zygote or in adult cells (a somatic mutation).
  Somatic mutations may underlie the origins of
  cancerous transformation of cells. And some
  genetic abnormalities are transmitted as familial
  traits, such as sickle cell anemia.

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• 7. Nutritional imbalances
• Protein-calorie deficiencies are the most
  examples of nutrition deficiencies. Vitamins also
  are rampant in deprived populations and are not
  uncommon even in industrialized nations having
  relatively high standards of living. Ironically,
  excess in nutrition are important causes of
  morbidity and mortality. Excess calories and dies
  rich in animal fat are now strongly implicated in
  the development of atherosclerosis. Obesity alone
  leads to an increased vulnerability to certain
  disorders, such as atherosclerosis, coronary
  heart disease, diabetes mellitus

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• 8. Aging
• Programmed aging whereby after a defined
  number of divisions the cell undergoes terminal
  differentiation.
• Development of an increasing population of
  cells irreversibly committed to senescence and
  death.
• Increased susceptibility to somatic mutation
  and a build-up of errors leading to an eventual
  error catastrophe.
• Faulty DNA repair mechanisms.