Final answer:
Osteocytes originate from osteoblasts that become entrapped within the calcifying bone matrix they create, leading to their transformation into osteocytes, the primary cells of mature bone.
Step-by-step explanation:
Osteocytes are derived from osteoblasts that become trapped in the matrix they secrete. These osteoblasts are responsible for forming new bone by synthesizing and secreting the collagen matrix and calcium salts. During the process of bone formation, as the matrix calcifies, the osteoblasts become entrapped within it. Consequently, they undergo structural changes and become osteocytes, the primary cell of mature bone and the most common type of bone cells. Each osteocyte resides in a space called a lacuna and maintains the mineral concentration of the matrix via the secretion of enzymes. Unlike osteoblasts, osteocytes do not divide and they can communicate and receive nutrients via long cytoplasmic processes called canaliculi that run through the bone matrix.