Final answer:
Bone remodeling is an essential lifelong process where bone is continuously resorbed and regenerated by osteoclasts and osteoblasts. It allows bones to adapt to stress and maintains strength, but disruptions can result in unsound bones prone to fractures, as seen in osteoporosis.
Step-by-step explanation:
Bone remodeling is a continuous, lifelong process in which bone resorption and regrowth occur, involving the activity of osteoclasts that dissolve bone and osteoblasts that form new bone tissue. This cycle of resorption and formation allows bones to adapt to stress, becoming stronger and thicker when subjected to regular stress. Conversely, bones that do not experience such stress, such as when immobilized in a cast, can lose mass. A fractured or broken bone repairs itself through a multi-stage process involving a temporary cartilaginous matrix called an internal callus and bone remodeling to strengthen the healing bone. However, if the balance between resorption and formation is disrupted, the bone may become unsound and more prone to fractures, a condition that may escalate in diseases such as osteoporosis.
This remodeling is responsible for shaping the skeleton, repairing minor defects, and helping maintain mineral balance. Approximately 5 to 10 percent of an adult's skeletal mass undergoes remodeling each year without the influence of injury or exercise, signaling the dynamic nature of our osseous tissue. Key nutrients like calcium play a critical role in this process, and insufficient levels can adversely affect bone strength and health.