Question

Why do old age people after a fracture take much time in rejoining the bones?

Answer 1

Calcium is the major component of bones. Due to aging, calcium, and calcium deposits on the bones keep on decreasing.

Complete solution:
Human bone consists of two competing cycles, namely breakdown and regeneration. Osteoclasts are specialized cells that have the ability to absorb worn-out cells of bones. These specialized cells constantly keep on removing the damaged cells from the bones. At the same time, another type of cell, known as osteoblasts, take calcium from the blood and then redistribute it among the bones. This process continues throughout our life. Until we reach the age of 20, bones are mainly focused on just one thing, i.e., growing. Bones continue to lay down new bone cells, even after achieving a maximum height. They do so for making the bones thicker and denser. As we grow older, our osteoblasts i.e., bone builders cannot match up with the activity of osteoclasts, which are responsible for the removal of damaged bones.
But in the case of older adults, suffering from a bone fracture, the body put more effort and resources toward the break. But the bone itself is already involved in a losing cycle of bone removal and replacement, as a result of which more bone is removed rather than being replaced. This cycle of bone removal and replacement very well explains the reason why older ones take longer to heal.

Note: In the case of children, the osteoblasts are constantly in a phase of laying down and building a new one. When a bone breaks in the body of a child, the body puts more effort in providing repair cells to the location of the injury. This is the phase when the bone is already engaged in a supercharged rate of growth. Hence, a child comes back to normal within a few weeks, whereas an adult takes six weeks or even more.