What are lacunae?

• A. Liquid stored in joints
• B. Large cavities in the lungs
• C. Small spaces in bone or cartilage where cells are located
• D. Tissues responsible for muscle contraction

Answer: (C)

Lacunae are defined as small spaces within bone and cartilage that serve as housing for cells, specifically osteocytes in bone and chondrocytes in cartilage. These tiny cavities provide a protected environment allowing the cells to maintain their functions while being embedded within the rigid matrix of the tissue. In bone, for instance, the lacunae are interconnected by tiny channels known as canaliculi, which facilitate communication and nutrient exchange between the osteocytes and the blood supply. This structural feature is crucial for the health and maintenance of skeletal tissue.

In contrast, the other options do not accurately describe lacunae: liquid storage in joints refers to synovial fluid, large cavities in the lungs pertain to pulmonary structures, and tissues responsible for muscle contraction are muscles themselves, which are distinct from bone and cartilage.