Bone remodeling

Bone remodeling is a special process that happens all the time in our bodies. It helps keep our bones strong and healthy. This process has two main steps: taking away old bone and building new bone.

This process is important because it lets our bones change shape or heal after we get hurt, like when we break a bone.

Scientists have found that tiny blood vessels in our bones help control this process. These blood vessels connect the cells that break down old bone with the cells that build new bone.

When we are babies, almost all of our bones are replaced in the first year of life. As we grow older, this process slows down, but it still keeps happening. In adults, about 10% of our bone is replaced each year. If this balance is disturbed, it can lead to problems like osteoporosis, where bones become weak and break more easily.

Physiology

Bone health needs many cells and signals to work together. Two main cells are osteoblasts, which build new bone, and osteoclasts, which break down old bone. For bones to stay strong and have enough calcium, these cells work with others, like immune cells, where bone is changing.

The body uses signals such as parathyroid hormone, vitamin D, growth hormone, steroids, and calcitonin to control how fast these cells work. This helps keep the right amount of calcium in the body. Bone remodeling is a constant process that keeps our bones healthy.