One of the many things about the human body that we don't appreciate enough is that it has a lot of reserve capacity. Namely, our organs have more 'reserves' than most of us will ever need, writes d. Robert H. Shmerling, from the portal Harvard Health Publishing.
"It's as if our bodies were designed with the idea that we might need help in case of illness or injury. And here's the thing: when everything goes well, we're born with two healthy kidneys, not just one.
And the kidneys are not the only example. So why are we 'built' with natural 'duplicates'? And what are the parts of the body that can fail, and there is a 'replacement'?
The likely answer is evolution: Early humans with a genetic makeup that produced organs with 'excess' capacity were better able to survive, thrive, and reproduce than species that weren't so built. As a result, genes associated with extra organ capacity—that is, two kidneys rather than one—are more likely to be passed on to future generations.
Meanwhile, ancestors who didn't have as much in reserve may not have survived long enough to reproduce, so they weren't as successful at passing on their genes. Over thousands of years, this power of natural selection has resulted in modern humans having a 'spare'.
Here is a partial list of organs where there is a 'reserve':
Eyes: You can be perfectly healthy with one eye, although you may lack the depth perception and wider field of vision that you have with two. Even the loss of both eyes does not directly lead to poor health, although blindness brings challenges and affects the quality of life. In addition, studies show that significant visual impairment can increase the risk of Alzheimer's disease.
Ears: Although two ears allow us to locate sounds from all directions, hearing loss in one or both ears does not immediately affect overall health. Alim, as with vision loss, quality of life can be reduced by hearing loss. As with vision loss, recent studies show that people with hearing loss are at increased risk of developing cognitive problems.
Intestines: Relatively large parts of the small and large intestines can be removed without much impact on health. In fact, the entire colon can be removed without shortening a person's lifespan, although frequent diarrhea or other symptoms may follow. Removing part of the intestine is a relatively common operation (eg for colon cancer) and does not shorten life expectancy.
Kidneys: Most people can live perfectly well with only one kidney. That's why people can donate a kidney to someone who needs it. However, the remaining kidney has to work harder, and the risk of future kidney failure increases somewhat. In addition, an injury, infection, or other disease affecting the remaining kidney can cause kidney failure more quickly than usual.
Lungs: When necessary, the entire lung can be removed, and you can rely on the other and function quite well. Lungs are most often removed for tumors, sometimes for infection or emphysema.
Liver: A relatively large part of the liver can be removed (assuming the rest of the liver is healthy) because there is so much "spare" liver tissue and the organ has the ability to regenerate. and the organ has the ability to regenerate.
Does this mean that many parts of our body are irreversibly expendable and some are not? Can be. If we think only of survival, we can consider many parts of the body as expendable, but we could survive without the spleen, most of the liver, eyes, ears, one lung, one kidney, and some other body parts. Moreover, millions of people around the world owe their survival to this very fact, and organ donors can help those in need and continue life normally, reports 24sata.
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