Eli5: How do bones and other organs know what shapes to grown into?
In: 3675
How about when bones or other organs are supposed to stop growing. Let’s say a particular bone is supposed to grow until a person is 15 years old and then not get any longer. Who told the cells when 15 years was up?
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Maybe see bone expert can ELI5 too. coworker had a broken elbow then later one piece of the elbow never stopped growing so he said he had to get it lasered off or something periodically. (no idea how that works cuz doesn’t laser burn your flesh too to get to the bone?)
Also I’m amazed at how the body knows to heal. I broke my collar bone and got a plate put in. Every few weeks I went back to my surgeon and we could see my bones fusing together in the x rays.
Your body has many copies of the same book that tell the body what to do, like a lego book tells you how to build a lego set. Sometimes it gets it wrong but its usually right.
Because the cells that form them are very smart, and learned over millions of years the best ways to grow that would make the whole person live the longest.
There. Actual ELI5.
You kinda have to take college level biology, chemistry and anatomy & physiology (A&P) to gain the ABCs of the medical world, with the latter being the meat of it all. The chemistry and biology are the jumping-off point.
Also, what stage at human development are we talking about? In utero? Adolescent? Post-injury as an adult?
If I had to give just one answer I would say that mesenchymal cells are at the center of it all, and they give rise to all the more specific types of osseous progenitor cells.
I use building analogies with my niece and nephew to describe ‘developmental biology’, since they live in houses and know most of the everyday items.
When you build a house, you start with a piles of bricks, piles of wood, tiles, and the like. You could build lots of different houses (body plans in our analogy) from those same materials, so you need a house blueprint to tell you how to put everything together (which inside us is our DNA).
When you start “building” it’s very simple, just a roof, walls, and basement if your type of house has them (this is like the skin, skeleton, and muscles in us) – and at the beginning its still pretty easy to make changes, very little is locked in. Once you’ve laid out the area for the kitchen, bathrooms, bedrooms, etc, then you start on the more intricate parts. Air-conditioning vents are like the vascular system, outlets and wiring are like the nervous system, and piping is like the digestive system. By this point it’s harder to make big changes. You might be able to move a sink from one part of the bathroom to another, but moving the kitchen to the other side of the house is going to be impossible.
The important part of the analogy is the blueprint doesn’t build the house, just like our DNA doesn’t build us. It’s just the instructions followed by the workers (proteins and transcription factors). Some parts of the blueprints are specified in exact detail (the door goes here!), other parts are up to the workers on some level (the floor is hardwood, now build it, I’m not telling you exactly where to cut each single piece of wood but here’s a rule about how they align).
For a eli5 discussion and without going into all the painful details – just know all the worker rules and instructions aren’t known yet (how we get from blueprint to structure) and that’s what biologists are working so hard to figure out.
But what programmed/created the dna and the sequencing? Not a religious post, I just want to understand the how?
same way that a giant building is made – construction managers know when and where certain structures need to go and in what order.
growth factors and other communications molecules deliver that information in a two-way cascade.
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