Which statements correctly describe compact bone? Multiple select question. It is solid and relatively densein flat bones, it is called diploeit is porousit forms the external walls of a long boneit contains trabeculae
The Correct Answer and Explanation is:
The correct answers are:
- It is solid and relatively dense.
- It forms the external walls of a long bone.
Explanation
Compact bone, also known as cortical bone, is a dense, strong type of bone tissue primarily responsible for providing structure and support to the skeletal system. It is crucial to understand its characteristics in relation to other bone types, such as spongy bone, to appreciate its unique functions.
- Solid and Relatively Dense: Compact bone is structurally very dense, with minimal spaces, which gives it a solid appearance when viewed in cross-section. This density is essential for withstanding compressive forces and protecting internal bone structures. The density of compact bone makes it much stronger than spongy bone, allowing it to bear the body’s weight and absorb impact forces efficiently. The compact bone’s tightly packed arrangement is due to the osteons, or Haversian systems, which are cylindrical structures that organize osteocytes (bone cells) in concentric rings around a central canal.
- Forms the External Walls of a Long Bone: Compact bone typically forms the outer layer, or “cortex,” of bones. In long bones, such as the femur or humerus, compact bone surrounds the spongy, or cancellous, bone inside. This positioning of compact bone as an external layer offers structural integrity and allows the bone to resist bending and torsion.
Why the Other Options Are Incorrect
- “In flat bones, it is called diploë”: This is inaccurate because, in flat bones like the skull, the term “diploë” refers to spongy bone, not compact bone. Diploë is the internal layer of spongy bone sandwiched between two thin layers of compact bone.
- “It is porous”: Compact bone is not porous like spongy bone. Its structure is much denser and more solid, which is why it provides greater strength and rigidity.
- “It contains trabeculae”: Trabeculae are the lattice-like structures found within spongy bone, not compact bone. Spongy bone’s trabecular network makes it lighter and better suited for areas needing shock absorption, like the ends of long bones.
In summary, compact bone is characterized by its density and structural function in forming the external framework of bones, particularly long bones, to provide rigidity and support.