Great question Sarah! Bones are made mainly of calcium that is laid down by bones cells in a regular lattice so that it is more robust. When kids grow special cells at the end of the bones refill the lattice with new calcium atoms so that they becomes longer. When you reach the age of 18-21 these special cells stop working and your bones do not grow anymore.
Hi Sarah! Noticed how baby’s have tiny little fragile bones compared to adult bones? There’s such a drastic size difference, both in thickness and length. How do they change size so quickly? You would think that to make a bone longer you d just need to add bone tissue to the end of it? It doesn’t quite work that way since we have joints that allow us to move our legs and if we added bone there, well, we wouldn’t be able to move! So for bone growth to work, bone tissue must be added below the joint somewhere along the length of the bone, at the epiphyseal plate, or growth plate. Hhyaline cartilage is produced and the cartilage then becomes calcified to form hard bone tissue (bones are made of a network of calcium deposited there by cells in our body). Bones reach maximum length at adulthood, so only then does the whole plate gets calcified. Great question again – good job 🙂