Question

what structure(s) occupie(s) the space labeled \lacuna\?

a blood vessels and nerve fibers.
b an osteocyte.
c a chondrocyte.
d this is the track left by an osteoclast.

Explanation:

🆕 New Concept Discovered: Structure of Compact Bone
How bone tissue is organized at the microscopic level

Step 1: Identify the tissue type

The image shows a microscopic view of compact bone tissue. Key features of compact bone visible here include:

• Osteon: The basic structural unit of compact bone, consisting of concentric layers of bone matrix.
• Haversian canal: The central channel containing blood vessels and nerves.
• Lacunae: Small, dark, almond-shaped cavities arranged in concentric rings.

Step 2: Determine the contents of a lacuna

A lacuna (plural: lacunae) is a tiny space or cavity within the hard bone matrix.

• In living bone tissue, each lacuna is occupied by a mature bone cell called an osteocyte.
• Osteocytes maintain the surrounding bone matrix and communicate with neighboring cells through tiny channels called canaliculi.

Step 3: Evaluate the options

• A. Blood vessels and nerve fibers: These are located in the central Haversian canal, not the lacunae.
• B. An osteocyte: This is correct. Mature bone cells (osteocytes) reside inside the lacunae.
• C. A chondrocyte: Chondrocytes are cartilage cells. While they also live in lacunae, they are found in cartilage tissue, not bone tissue (osteons).
• D. This is the track left by an osteoclast: Osteoclasts are large cells that resorb (break down) bone tissue on bone surfaces; they do not live inside lacunae within osteons.

Answer:

B · An osteocyte.