oxygen free radicals

cellular damage

free radicals are "free" because they are missing a critical molecule, which sends them on a rampage to pair with another molecule. When free radicals are on the attack, they don't just kill cells to acquire their missing molecule. If free radicals simply killed a cell, it wouldn't be so bad. the body could just generate another one. The problem is, free radicals often injure the cell, damaging the DNA, which creates the seed for disease. When a cell's DNA changes, the cell becomes mutated. It grows abnormally and reproduces abnormally -- and quickly.

theories of aging

free radicals damage cells in the body causing us to age

inactivation or termination of free radicals

processes resulting in inactivation or termination of free radicals by quenching the lone electron in the outer shell of the free radical -antioxidants block synthesis or inactivate free radicals

free radicals may be formed by:

-normal cellular processes -exogenous sources -enzymatic metabolism of chemicals (CCL4, carbon tetrachloride) -an acute bout with exercise in a sedentary person (generates abundant amounts of free radicals)

necrosis

-premature death of cells and living tissues -detrimental -pathologic "cell homicide" -inflammation and surrounding tissue damage -large number of cells and swelling

apoptosis

-process of programmed cell death -beneficial -physiologic "cell suicide" -no inflammation and no secondary tissue damage -few cells and shrinkage

reperfusion continued

-the body tissues forget how to protect themselves from free radical damage -in healthcare we are constantly dealing with reperfusion -now tissues that were hypoxic are now reperfused -recognize that cells that may have been hypoxic may have forgotten how to protect themselves from free radical damage -reperfusion is important for cell resurvival, BUT there may continue to be damage to those cells when reperfusion occurs

free radicals formed by exogenous sources:

-tobacco smoke -certain pollutants and organic solvents -pesticides -radiation -UV light -x rays External toxins, especially cigarette smoke and air pollution, are "free radical generators". "Cigarette smoke is a huge source of free radicals. Our food and water also harbor free radicals in the form of pesticides and other toxins.

vitamin E

-type of antioxidant -neutralizes free radicals when they bond to phospholipids -neutralizes the oxidant effect of free radicals

reperfusion injury

1) normally, cells have chemical mechanisms to protect themselves from free radical damage (endogenous antioxidants) 2) during hypoxia from ischemia, these protective mechanisms break down, are inactivated, or damaged 3) during restoration of blood flow with oxygen (reperfusion), cells may not be able to protect themselves from free radical damage

membrane, DNA, and protein damage

?? When cells create energy, they also produce unstable oxygen molecules. These molecules, called free radicals, have a free electron. This electron makes the molecule highly unstable. The free radical bonds to other molecules in the body - causing proteins and other essential molecules to not function as they should.

free radical

-electrically charged atom/ group of atoms having an unpaired electron that leaks out during the process of oxidative phosphorylation. -Oxygen molecule that has lost an electron. This electron loss makes it positively charged -associated with over 200 disease processes these are the *Leading theory of aging*

enzymes

-endogenous antioxidants -SOD, CAT, and GHX -research indicates that chronic exercise results in elevated levels of these ^

antioxidant sources

-endogenous or exogenous -vitamin E and vitamin C -beta carotene -cysteine -glutathione -albumin -transferrin -BERRIES AND VEGETABLES!

free radicals formed by normal cellular processes:

-energy generation: oxidative phosphorylation (phase 3 metabolism) -lipid peroxidation (cell wall remodeling) -protein catabolism -inflammation -white blood cells killing a bacterium Normal cell functions produce a small percentage of free radicals, much like a car engine that emits fumes. But those free radicals are generally not a big problem. They are kept under control by antioxidants that the body produces naturally

antioxidants

Antioxidants are substances found in plants that soak up free radicals like sponges. If your body has plenty of antioxidants available, it can minimize the damage caused by free radicals. Get your antioxidants from eating plants.

results of free radical damage:

cellular injury to cell membranes and nucleic acids 1) lipid peroxidation: destruction of unsaturated fatty acids in cell walls.It is the process in which free radicals "steal" electrons from the lipids in cell membranes, resulting in cell damage. 2) protein fragmentation 3)DNA alterations