What do osteoblasts primarily do when signaled by the blood to begin their activity?

Osteoblasts are specialized cells that play a key role in bone formation. When signaled by the blood, typically through hormones such as parathyroid hormone (PTH) or calcitonin, osteoblasts primarily deposit bone material, which consists of collagen and inorganic mineral components such as hydroxyapatite. This process is crucial for the growth and healing of bones as it enables the increase of bone density and strength.

Moreover, osteoblasts not only contribute to the initial formation of bone but also become embedded within the bone matrix and differentiate into osteocytes, which maintain the bone tissue. The deposition of bone material is essential for both maintaining bone structure and responding to mechanical stress or injury. Therefore, the activity of osteoblasts in depositing bone material is a fundamental aspect of bone health and metabolism.