Mary Allen
Bones are hard parts of the body that support it. They also form a protective layer: the skull for the brain, and the ribs for the chest. All together form the skeleton.
Animals and humans don’t always have the same types of bones. Birds, for example, have tubular bones filled with air so that they are lighter and can fly well. The bones of fish are called bones.
What parts are bones made of?
Bones consist primarily of bone tissue, bone marrow, and the periosteum. On the one hand, bone tissue consists of hard parts, which give it stability. These are minerals with a lot of lime. On the other hand, the bone contains soft parts made of proteins, which give it elasticity. These parts are also called bone glue.
Bones grow with the body because they are living organs. But they also change: children’s bones contain a lot of bone glue, which is why they are so soft and elastic. Older people’s bones contain more minerals. They, therefore, break more easily.
Each bone is covered by a thin periosteum. The periosteum is very sensitive to pain. You notice that, for example, if you hit your shin.
Inside the bone is the bone marrow. Blood is regenerated and constantly replaced in the bone marrow. That is why there are many veins in the bones.