Why exactly is happening inside our bodies to bring on the wrinkles,grey hair and other changes seen in older people?
Answers
Much of it depends on the type of cell you are describing because different cells in our body age differently by regenerating at different rates.
There are myriad processes involved, but there are a couple short answers.
Regardless of exposure to any environmental influences, people will age as their telomeres shorten. Telomeres are a sort of cap on the ends of chromosomes that help protect wonky things from happening as cells divide and replenish themselves. As people age, their cells’ telomeres get shorter and shorter. There is also a general sclerosis, or hardening of tissues, which is believed to be caused by advanced glycation end-products (AGEs), i.e. the by-products of metabolic processes.
Talking about telomeres never really translates well to talking about wrinkles, grey hair, etc., however. Most people are only concerned with the external effects of aging.
Sarcopenia is a term for muscle mass decreasing as people age, which can make their posture a little more stooped, their balance precarious, and their faces seem sunken or withered. Older adults may have had their teeth fall out or removed and this can also make people appear withered and older. Grey hair is essentially pigment cells in hair follicles dying. Other common diseases of aging such as cataracts and arthritis, can cause changes in outward physical appearance as well.
The most important thing to remember is that less wrinkles does NOT equal more healthy. There is so much more going on in our cells as we age than what is apparent on the outside
the cells change themselves according to our age that's why it happens