Height is determined by length of the long bones and skeleton. Arms and legs have special areas across them (below the knees and wrists) called “growth plates” made from flexible cartilage. The cartilage is turned into hard bone in these areas by bone cells, called bone matrix. Matrix itself is made of a material called “hydroxyapatite” and it is like a chalky ceramic. Matrix is added a layer at a time onto the end of the plates, gradually making the bone longer.

Growth is what we know as the increase in the size of the body with age. We can see this by measuring either height or weight. In babies, this is also done by measuring the roundness of the head (circumference) and their length from head to toe.

Metabolism can be a confusing concept to understand, but it is critical to how children grow and develop. All the cells in a child’s body use a tiny amount of energy to divide and make copies of themselves, and the do it all by themselves. They do this by breaking down the nutrients and extracting the energy from them – this is called “metabolism”.

Soft bone development begins during pregnancy at 7 weeks, and is most active during the third trimester. After birth, the bones become hardened through a process called “ossification” . Until then, bones are mostly made of cartilage at birth, which is soft and rubbery.