Micro Life Zone
Asked by cocacolarulez to Arti, Chris, Dustin, James, Steven on 18 May 2012.
Keywords: bone, bones, human
Hey @cocacolarulez. Bones are made of a network of calcium laid down by cells. As kids grow, special cells at the end of bones add new calcium to the network of the existing bone. Children have layers of these cells in the shape of plates at the ends of their bones. These are called growth plates, and they close up when kids reach their full adult height. The growth plates are open when you are born and the more and more that you grow, the more closed they become and eventually close for good when you are fully grown, which is usually around the age of 16 for the average child.
The amount of calcium laid down by cells is ultimately regulated by your DNA and genetic make up.
Chris has this, good’o
Well answered Chris
Well answered, Chris.
Cocacolarulez, you might be interested to know that the reason girls are shorter than boys on average is because of oestrogens, the ‘female hormones’. When we reach puberty, males start to produce more testosterone (the ‘male hormone’) while females start to produce more oestrogens that we did when we were younger. Oestrogens affect the growth plates that Chris mentioned, and make them close up quicker in girls than they do in boys.
Also, our bones stop growing longer in our teens, but our bones are actually still growing and remodelling all the time. Stresses on your bones, such as weight-bearing exercise cause your bones to grow thicker at the point of stress, and so help to make them stronger. Bone remodelling is controlled by cells located on/close to the bone surface called ‘osteoblasts’ (the bone-building cells) and ‘osteoclasts’ (which break down bone), which are active throughout our lives.
Bone remodelling can also occur if we don’t have enough calcium in our body. We need to have a certain level of calcium present in our bloodstream at all times, so if we don’t have enough in our blood, our body will take it out of our bones! So if you don’t take in enough calcium through our diet, our bones will keep becoming weaker and this is how we develop conditions such as osteoporosis (which kind of means ‘porous bones’). We also need plenty of vitamin D for us to have good calcium levels and bone health. Vitamin D can be made inside our bodies when we are exposed to sunlight (you can take vitamin supplements, too), so that is one reason we need to have some sun exposure everyday (safely, of course!). People who don’t get enough vitamin D or sun exposure can develop a bone disease called Rickets, in which the bones become softer and brittle, and become more bent/curved instead of being straight.
Make sure you keep drinking plenty of milk (or getting calcium from other sources) and getting some regular, safe sun exposure!
By BRIDGE8 under license from Mangorolla CIC 2023