The aging process is not fully clear yet and a number of theories is suggested to explain aging changes and associated hazardsas:
-Defective synthesis of protein
-Faulty repair of DNA
-Accelerated wear and tear (may play a role)
-Free radicals theory.
Free Radicals are hightly reactive chemicals that must be inactivated by different defence systems of the body,otherwise their reactivity can involve and damage the body cells.Are those implicated in the etiology of different degenerative diseases.
Free radicals are externally introduced (exogenous) or internally produces (endogenous) sources.
Externally introduced sources of free radicals:
-exposure to radiation (the ultraviolet)
-some drugs,specially when exist an abuse of it
-inhalation of certain air pollutants,including pesticides
-exposure to ozone
-cigareete smoking.
Internally produced sources of free radicals:
-some metabolic processes of the body that produce reactive oxygen species (oxidantive metabolic process)
-inflammatory and ischemic processes and others.
Free radicals and other oxidants are cell oxidizers described as cell destroyers.The molecules of oxidants are not readily metabolized in the body and so accumulate leading to irreversible cell damage.
Antioxidant defensive mechanism of the body protects the cells against their destroying effect.But,formation of free radicals and oxidants,together with impaired antioxidant defences,predispose to cell deterioration and degenerative diseases,specially of elderly.
Harmful oxidative effect involves proteins,carbohydrates,lipids and DNA,and plays an important role in pathogenesis of degenerative of degenerative diseases of aging for exemple:
-artherosclerosis and associated cardiovascular and cerebrovascular disease.
-cancer
-cataract
-neurodegenerative process (Alzheimer's disease).
Can appear the Oxidative Strees:
Is the adverse condition that results from imbalance between high exposure to sources of oxidants and antioxidants defence of the body.
Antioxidant Defence of the Body:
They combate the harmful effect of free radicals and other oxidants.
1.Enzyme-are antioxidants that react with the oxidizing chemicals and diminish the concentration of harmful oxidants in the body and protect the body against their damaging effect.
2.Antioxidants vitamins: vitamin A,C and E.This protect the cells by binding electrically unbalanced free radicals and prevent deposition of cholesterol in arterial walls and so protect the heart and limit progression of degenerative disease and premature aging.
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