Bone remodeling

Bone remodeling is a special process that happens all the time in our bodies, helping to keep our bones strong and healthy. It involves two main steps: taking away old bone and building new bone. This process is very 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, called Type R endothelial cells, help control this process. These blood vessels connect the cells that break down old bone with the cells that build new bone, making sure everything works together properly.

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 involves many working cells and signals. Two main types of cells help with this: osteoblasts, which build new bone, and osteoclasts, which break down old bone. For bones to stay strong and have enough calcium, these cells need to work together with others, like immune cells, at places where bone is being changed.

The body uses many 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 for important jobs. Bone remodeling isn’t just fixing damage; it’s a constant process that happens all the time to keep our bones healthy.