Final answer:
Extrinsic causes of micro insults in aging include environmental and lifestyle factors that contribute to secondary aging, such as lack of exercise, poor diet, and exposure to harmful substances. These can lead to disease and exacerbate the decline in tissue function and appearance accompanying primary aging.
Step-by-step explanation:
Extrinsic Causes of Micro Insults in Aging
Micro insults refer to minor but persistent damage to the body's cells and tissues. When considering extrinsic causes of these micro insults, several factors related to environmental and lifestyle choices are implicated. Aging, as a natural biological process, involves both intrinsic factors like genetics and cellular metabolism, termed as primary aging, and extrinsic factors, referred to as secondary aging. Secondary aging is influenced by controllable factors such as lack of physical exercise and poor diet. Over time, these lifestyle choices can lead to the accumulation of waste products in cells and an overabundance of free radicals like OH- (hydroxyl radicals), which can damage DNA and cells, eventually contributing to diseases like cancer and cardiovascular disease. These diseases are more prevalent in the latter decades of life and increase with exposure to environmental pollutants, consumption of alcohol, intake of trans fats, and smoking tobacco. Essentially, secondary aging can exacerbate the natural decline in tissue function and appearance that occurs with primary aging.
In the context of aging, micro insults are not solely due to aging itself. They can also occur because of exposure to external factors such as ultraviolet radiation, which can further deteriorate skin by reducing its ability to retain moisture, diminishing the production of essential structural proteins like collagen and elastin, and weakening underlying muscle tone. This kind of environmental damage accelerates the visible signs of aging and can also reduce general immunity.