What is the primary function of osteoclasts in the context of bone health?

• A. They lay down new bone
• B. They digest old bone
• C. They regulate calcium levels in the blood
• D. They stimulate cartilage cell division

Answer: (B)

Osteoclasts play a critical role in bone health primarily through their function of breaking down old bone tissue. They are specialized cells responsible for the resorption of bone, which is a vital process in the maintenance, repair, and remodeling of bones. This activity helps maintain the balance between bone formation and resorption, which is essential for bone strength and overall skeletal health.

The process of bone resorption involves osteoclasts attaching to the bone surface and creating an acidic environment that dissolves the mineral component of the bone and releases enzymes that break down the organic matrix. This action not only helps to remove damaged or aged bone but also enables the release of calcium and phosphate into the bloodstream, which are crucial for various physiological functions.

Understanding the function of osteoclasts is essential, as imbalances in their activity can lead to conditions such as osteoporosis, where excessive bone resorption occurs, leading to decreased bone density and increased fracture risk.