Compact bone

Definition

Compact bone is a dense and strong type of bone tissue that forms the outer layer of bones, providing strength and support. It is organized into structural units called osteons, which consist of concentric layers of mineralized matrix surrounding a central canal that houses blood vessels and nerves. This highly organized structure allows for efficient weight-bearing and resistance to bending and fracturing.

5 Must Know Facts For Your Next Test

1. Compact bone makes up about 80% of the total bone mass in the human skeleton, providing the strength needed for daily activities.
2. The mineralized matrix in compact bone primarily consists of hydroxyapatite, which gives the bone its rigidity and ability to withstand compressive forces.
3. Compact bone contains fewer spaces compared to trabecular bone, making it denser and better suited for supporting weight.
4. Osteocytes, which are mature bone cells, reside in small cavities called lacunae within the compact bone matrix and play a crucial role in maintaining bone tissue.
5. The outer layer of compact bone is covered by a thin connective tissue membrane called the periosteum, which contains blood vessels and nerves that nourish the bone.

Review Questions

• How do osteons contribute to the function of compact bone?
  • Osteons are essential for the function of compact bone as they provide a strong framework through their organized structure. Each osteon consists of concentric layers of mineralized matrix that surround a central canal containing blood vessels and nerves. This organization allows for efficient nutrient delivery and waste removal while ensuring that compact bone can withstand significant mechanical stress.
• Compare and contrast compact bone with trabecular bone in terms of structure and function.
  • Compact bone and trabecular bone differ significantly in both structure and function. Compact bone is dense and forms the outer layer of bones, providing strength and support for weight-bearing activities. In contrast, trabecular bone has a porous structure with an internal network of struts that reduces weight while still providing structural support. This allows trabecular bone to absorb shock and accommodate changes in stress on the skeletal system.
• Evaluate the importance of bone remodeling in maintaining healthy compact bone throughout life.
  • Bone remodeling is crucial for maintaining healthy compact bone as it allows for continuous adaptation to mechanical stress, repair of micro-damage, and regulation of calcium levels in the body. This dynamic process involves the coordinated action of osteoclasts, which break down old or damaged bone tissue, and osteoblasts, which form new bone. By adjusting the density and strength of compact bone over time, remodeling ensures that bones remain resilient against fractures while also responding to changes in activity levels or nutritional status.

Related terms

Osteons: The structural units of compact bone, consisting of concentric layers of bone matrix around a central canal containing blood vessels and nerves.

Trabecular Bone: Also known as spongy bone, it is less dense than compact bone and has a porous structure, found mainly at the ends of long bones and in the interior of others.

Bone Remodeling: The ongoing process of bone resorption and formation that allows bones to adapt to stress, repair damage, and maintain overall skeletal health.