American Board of Orthodontics (ABO) Practice Exam

What is the primary physiological role of osteocytes?

1. Bone remodeling

2. Bone formation

3. Bone resorption

4. Maintenance of bone tissue

The correct answer is: Maintenance of bone tissue

The primary physiological role of osteocytes is the maintenance of bone tissue. Osteocytes are mature bone cells that originate from osteoblasts, which are involved in bone formation. Once the osteoblasts have completed their role and become embedded in the mineralized bone matrix, they differentiate into osteocytes. These cells play a crucial role in the maintenance of the bone's microenvironment and homeostasis. Osteocytes are essential for the repair and remodeling of bone. They communicate with each other and with osteoblasts and osteoclasts (the cells responsible for bone resorption) through a network of tiny channels called canaliculi. This interaction allows osteocytes to regulate the activity of osteoblasts and osteoclasts, thereby helping to maintain bone density and structural integrity. They sense mechanical strain and biochemical signals, enabling them to respond to the mechanical demands placed on the bone, which in turn influences remodeling and health of the bone tissue. Thus, while osteocytes do indeed participate indirectly in bone remodeling and can influence both bone formation and resorption processes, their primary and most direct role is the maintenance of the bone tissue. This function is vital for ensuring that bones remain healthy and capable of responding to various physiological stresses.