Bone Balance

Our bones are constantly being recycled to keep them healthy. One type of cell in the bone breaks it down and another reforms it – a balance controlled by the brain, via networks of nerves running through our body. The sympathetic nervous system – the network responsible for immediate actions such as sweating and quickening the heart – restricts bone tissue formation, whereas the parasympathetic system – responsible for long-term actions such as digestion – is thought to stimulate it. Parasympathetic nerves, and receptors (seen here dyed red in a bone cell, called an osteoclast, from a mouse) have only recently been found in bone tissue. Understanding the balance is important for research into diseases such as osteoporosis, which is caused by excessive bone tissue loss, usually in later life, creating a high risk of fractures.

Written by Mick Warwicker

• Itai Bab
• Hebrew University of Jerusalem
• Published in PNAS 109(38): 15455-15460