What are the tightly compacted cylinders of bone in compact bone called?

The correct answer refers to Haversian systems, which are essential structural units of compact bone. Each Haversian system, also known as an osteon, consists of a central canal surrounded by concentric layers of bone matrix known as lamellae. The central canal contains blood vessels and nerves, which are crucial for providing nutrients and facilitating communication within the bone.

Haversian systems are characterized by their cylindrical shape and organized structure, which allows for efficient weight distribution and strength in bones. This arrangement of tightly packed components in a circular manner maximizes the compactness and enhances the mechanical stability of the bone.

While the term osteons can also be used to describe these structures, Haversian systems specifically highlight the combination of central canals and their surrounding lamellae. Therefore, understanding the context and implications of Haversian systems in bone anatomy is key to grasping how compact bone maintains its integrity and function.