What factors influence the amount of bone resorbed by a remodeling unit?

• A. Number of osteocytes, bone density, treatment type
• B. Osteoclast activity, number of osteoblasts, mechanical load
• C. Number of osteoclasts, rate of osteoclast work, lifespan of osteoclasts
• D. Age, activity level, nutritional intake

Answer: (C)

The correct response highlights the key components involved in the process of bone resorption within a remodeling unit.

Bone remodeling is a continuous process where old bone is removed and new bone is formed, involving osteoclasts and osteoblasts. Osteoclasts are specialized cells responsible for bone resorption. The amount of bone resorbed is influenced by the number of osteoclasts present, as having more osteoclasts can lead to increased bone breakdown. Additionally, the rate at which osteoclasts perform their function, or the speed at which they resorb bone, directly affects the total volume of bone being removed. Lastly, the lifespan of osteoclasts plays a crucial role; longer-living osteoclasts can contribute to more sustained resorption over time.

Simple mechanical or external factors, such as general activity level or nutritional intake, while influencing bone health indirectly, do not address the specific cellular dynamics at play in the immediate environment of a remodeling unit. Thus, focusing on the role of osteoclasts provides a clearer picture of the biochemical and cellular mechanisms directly involved in the resorption process.