Look – I’m not the smartest person nor the most insightful. I got high one evening and thought to myself, “hold up.. bones grow?”. And yes, I did get a very low mark in biology, but better the curiosity kick in now than never lol – so I apologize for my use of terminology.
I Googled a bit on it and had a hard time wrapping my head around what exactly is in the bones “hard-code” that makes it a main base of biological human foundation. How far have we come to understanding every component that makes it a bone? Guessing that it’s been studied in its entirety already considering medical advancements, but it just seems a little TOO overpowered to me.
Forgive me, I am also just remembering bones aren’t just in humans.
Anyway.
Our biological design startup sequence gives us this base structure (bone) for our anatomy setup, which in my head, I’m comparing to like metal beam supports of a building. And you’re telling me it GROWS? our metal beams have the power to GROW?
What’s been studied and tested when it comes to the material in bones and it’s growth? And have people tried testing the limits of its growth and what have they come up with so far?
I understand there’s defects like bone cancer which can make bones grow very unfavorably inside a living person. So a defect can push a bone to continue growing past it’s norm, but is that the only factor?
I have a lot of bone questions and I thought here would be a great place to start. If anyone could whip up a basic understanding of bones – it’ll help provide a better learning foundation for me to continue down this curious path.
Thank you!
In: Biology
I apologize if this was too simple of a question to ask considering the crickets in the comments 😭
The hard portion of your bones start off as a rubbery substance known as cartilage, which forms the space between the the mineral hydroxyapatite that forms the hard part of your adult bones. As you grow and eat food, enzymes in your bone tissue get to work at replacing the cartilage with hydroxyapatite up until your growth plates (the epiphyseal plates) fuse (ossify, turn to bone) and there’s no more cartilage left to replace.
Oh, and the increase in cross-sectional size and dimensions of the bone is due to the fact that the cartilage thickens and stretches as it’s replaced.
EDIT: Forgot to mention that your genes and their epigenetic tags (the biochemical markers that determine how much the gene is expressed, if at all) can also determine how many more bone-building enzymes and how much of that initial cartilage is built over. Puberty and one’s birth sex also plays a role in the rate at which bones are further ossified and built upon.
It’s important to remember that bones aren’t solid slabs of material. When you look at bone (or any other tissue) it’s not just cells hanging onto each other. There’s also a scaffolding around them made of protein that the cells build, and the whole structure is more like a honeycomb, or an apartment building where the cells are the tenants, not the structural elements.
When bones grow, the cells multiply at the growth plates, like if tenants in an apartment building had kids and those kids got together and built a new floor on the building to accommodate them. The whole structure grows over time, and the kids are following a blueprint so it grows correctly and there aren’t structural issues.
Bone cancer is like a population explosion, and the new kids don’t have the right blueprints, so they’re slapping things together from what they remember and hoping it works, but it grows out of control and the problems with the building get worse and worse over time.
There are other factors that can make bones grow – my brother was born with one leg shorter than the other by two inches, so he had to get an operation to lengthen the bone in that leg, which came down to breaking it and then slowly drawing the two edges of the break apart. The two broken edges tried to repair themselves, reaching out across the gap to shore things up, and by doing it slowly enough over time it was possible to get them to grow that two extra inches by exploiting that repair mechanism.
In addition to starting as cartilage and growing from growth plates as others have said, bones are alive and are constantly being broken down and reformed. There are specific cells whose job it is to break down bits of bone and to reform bone: osteoclasts and osteoblasts. When you break a bone it heals, it doesn’t just stay broken!
In addition to starting as cartilage and growing from growth plates as others have said, bones are alive and are constantly being broken down and reformed. There are specific cells whose job it is to break down bits of bone and to reform bone: osteoclasts and osteoblasts. When you break a bone it heals, it doesn’t just stay broken!
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