How can our body “regenerate” some tissue when we get wounded but can’t do it in a larger scale?



As an example, if you bite your tongue, as it heals, your own body generates tongue tissue. But if you cut it apart, your body os not able to create a new tongue.

Sorry for my english, i’m not native

In: Biology

Some organs like skin, digestive tract lining, and the blood have very active stem cells that are constantly dividing and replacing lost cells and tissue. Other cells in your body are more differentiated and “specialized”. They do not have the ability to begin dividing for the purposes of regeneration (replacing lost cells). Specialized cells age and breakdown over time (eye sight gets worse with age).

Side note: If you’re interested, there is some reading you might enjoy on the anti-aging impacts of intermittent fasting on your cells.

Think about this in evolution terms. When our ancestors suffered major injury, they usually died, but shutting the wound as fast as possible gave the best chances of survival. People who survived accidents could still have offspring and were albe to pass their genes. On the other hand if your serious wounds would keep regenerating, this means whole process has to take more time, more energy, and needs care. So in our mind we can see, that it would be more beneficial in present times, but evolution does not see. Its just what gives you best chances of reproduction. And it turns out its not regeneration for us.

Imagine the body part is a house. When you’re building it the plans and materials are readily available. When you’re developing the contractors (cells) that your body has are very skilled workers so you have a great architect, designer, electrician, carpenter, general contractor and they all work together to build up a house using the plans that all these special cells share and work together to complete.

Afterwards the plans get photocopied a bunch of times until they’re not so good anymore, the skilled workers have left and you’re left with the equivalent of the local handyman, there’s some left over materials from the build, flooring, drywall, paint, etc… If you break a window you don’t need to consult the plans to get it repaired, and the handyman can do it. Break up some flooring, grab some of the spare materials and you can do a patch job but you don’t have enough left to fully redo the floor. That’s also what causes scars, imagine you’re repairing a hardwood floor and the handyman lays the patch in the wrong direction. It’s still floor, just wrong.

You can see from the leftover materials and the local handyman that most small repairs are a cinch but if I drive a bulldozer over half the house the resources you have available to rebuild (handyman and leftover materials and barely decipherable plans that give you an idea of what it’s supposed to look like) are not going to be able to do much to help.

One of the goals of stem cell research is figuring out how to

1. Track down the original contractors

2. Find the original plans

3. Provide the body with the necessary materials and have them delivered