Final answer:
Compact bone is the dense outer layer designed to withstand compressive forces with an osteon structure, while spongy bone has a lighter, open network structure of trabeculae, aiding in weight distribution and housing bone marrow. Both types are crucial for bone health and functionality.
Step-by-step explanation:
Bones are composed of two main types of tissue: compact bone and spongy bone. Compact bone, or cortical bone, forms the dense outer layer of bones and is designed to withstand compressive forces. The osteons are its structural unit, containing a central Haversian canal surrounded by concentric lamellae, all interconnected by canaliculi. This arrangement contributes to the bone's strength and durability. Conversely, spongy bone, also known as cancellous bone, is lighter and found in the interior of bones, such as the epiphysis of long bones and the core of flat bones. It consists of a network of trabeculae, which are small, bony plates that provide structural support and accommodate shifts in weight distribution.
The cell arrangement in compact bone is in tightly packed columns, whereas in spongy bone it's more open and loose. This histological difference is crucial for the bones' various functions and locations within the body. Compact bone plays a primary role in protection and support, while spongy bone aids in weight distribution and houses the bone marrow. Over time, the trabeculae in the spongy bone can break down, making bones less resilient. Both types of bone tissue are integral to the skeletal system's overall health and functionality.