The ageing process is happening to each and
everyone one of us non stop, but what is exactly
occurring on a cellular level and why do our
bodies deteriorate over time? Let’s find
out what are some of the main causes of ageing!
There are plenty of factors that impact ageing,
and they can be internal and external. When
it comes to the external, environment features
such as UV light, diet, polluted air or water,
can have a huge impact on our health.
Internal factors on the other hand represent
the accumulation of defects that contribute
to the overall disruption of the body such
as genetic damage.
The way our body works is when the cells divide
they also replicate the DNA molecule. Our
DNA is tightly packed within chromosomes.
At the ends of these chromosomes are structures
called telomeres. Telomeres are there to protect
the DNA from losing the important information.
Every time cells divide, these protective
regions become shorter and shorter until they
eventually disappear. When this happens, cells
cannot divide anymore, and they die.
Another enemy of our cells is oxidative stress.
Reactive oxygen species, also called free
radicals, contain an unpaired number of electrons,
which makes them very reactive. These unstable
molecules are constantly being produced in
our body. Luckily, there are antioxidants
- molecules with the purpose of preventing
damage to our cells. But, sometimes free radicals
outnumber the antioxidants, and that is when
oxidative stress kicks in. Prolonged oxidative
stress can hurt your DNA and other vital molecules
causing potentially serious damage.
As DNA is essential for the synthesis of all
proteins, mutations within can subsequently
lead to the production of non-functional proteins.
Without correctly synthesized proteins, different
mechanisms within our cells are changed, as
they can no longer perform their role. Also,
these abnormal proteins tend to aggregate
and accumulate in many tissues during the
ageing process and are associated with different
diseases, such as Alzheimer’s.
As mitochondria have their own DNA, they are
also prone to free radical damage. Mitochondria
are known as the powerhouses of the cell.
This is because they provide ATP the main
source of energy for all cellular processes.
Random mutations of DNA lead to translational
errors and consequently to incorrectly synthesized
proteins. Cells become deprived of energy,
which furthermore causes reduced organ function
and eventually affects the whole organism.
Also, there are cells called - Adult stem
cells - that are found in many organs. They
provide new cells for the body as it grows
as well as regenerating cells that are damaged
or lost. As they are also affected by the
shortening of the telomeres and oxidative
stress, their number declines as the time
goes by.
Aging affects all living things on the planet,
from plants to animals and humans. But, why
has evolution not prevented aging in the ﬁrst
place? Well, one of the theories is because
natural selection has become incapable of
maintaining function and reproductive fitness
at old age. As species survival depends on
an adequate number of members that are capable
of reproduction, natural selection will favor
expansion in reproduction rather than increasing
individual longevity. So the energy is more
efficiently utilized, at least in the perspective
of evolution.
We pointed out here some of the main causes
of the ageing process. There are a lot of
mechanisms that are yet to be discovered and
that will help us to understand better why
and how we age. It is only a matter of time
before we can significantly slow down ageing,
but will we ever become immortal?
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