What are the differences between compact and spongy bone?

Compact and spongy bone are the two main types of bone tissue found in the human skeleton. While both types of bone are composed of the same basic materials, they differ in their structure and function.

Compact bone

* Structure: Compact bone is dense and solid, with few spaces between the bone cells. It is arranged in layers, or lamellae, that form a protective outer layer for the bone.

* Function: Compact bone provides strength and rigidity to the skeleton. It is found in the shafts of long bones, such as the femur and humerus, and in the flat bones of the skull and pelvis.

Spongy bone

* Structure: Spongy bone is less dense and more porous than compact bone. It has a honeycomb-like structure with many spaces between the bone cells. These spaces are filled with bone marrow, which produces red and white blood cells.

* Function: Spongy bone provides support and flexibility to the skeleton. It absorbs shock and cushions the joints. It is found in the ends of long bones, such as the knee and hip joints, and in the vertebrae of the spine.

In addition to their different structures and functions, compact and spongy bone also differ in their composition. Compact bone contains a higher percentage of minerals, such as calcium and phosphorus, than spongy bone. This makes compact bone harder and more brittle, while spongy bone is more flexible and shock-absorbing.

The combination of compact and spongy bone in the human skeleton provides a balance of strength, flexibility, and protection. This allows the skeleton to support the body's weight, protect the internal organs, and allow for movement.