(or 2!) Dying of old age, can you actually DIE because of the body being worn out, or is it always a disease or such? I read that if we cure every disease, we would live hundreds of years.

Question

Title! I don’t get it. Isn’t my finger getting worn from just being used for too long? Or will it eventually get worse because of something else?

In: Biology

Answer 1

Ageing causes diseases, but curing all diseases won’t stop you from ageing and dying. You are made of cells, which make up all kinds of systems, like organs and tissues. Some cells always die, and get replaced. Every time you copy a cell, the new cells will be a bit worse than the ones before. Eventually you not only have a lot of bad cells, you can’t even replace the ones you lose.

In more detail and less ELI2-5
Genomic instability, epigenetic alterations, loss of proteostasis and mitochondrial dysfunction causes all your cells to be less functional, dysregulated nutrient sensing, cellular senescence and altered intercellular communication makes all your tissues degrade, telomer attrition means fewer and fewer cells divide, and stem cell exhaustion means you can’t replace lost cells any more.

So regardless of disease your tissues and organs degrade untill the whole system collapses.

You can try to plug holes but if the ship disintegrates around you, you’ll sink sooner or later.