Compact bone

Definition

Compact bone is a dense and strong type of bone tissue that forms the outer layer of bones, providing structural support and protection. It consists of tightly packed osteons, or Haversian systems, which are cylindrical structures that facilitate the delivery of nutrients and removal of waste through a network of canals. This organization allows compact bone to withstand compressive forces and contributes to the overall strength and rigidity of the skeletal system.

5 Must Know Facts For Your Next Test

1. Compact bone makes up about 80% of the total bone mass in the human body, providing strength and structure.
2. The Haversian canal system within compact bone contains blood vessels and nerves, ensuring that the bone remains healthy and well-nourished.
3. Compact bone is essential for the mechanical support of the skeleton, helping to protect internal organs and withstand stress from physical activities.
4. The outer layer of compact bone is covered by a tough connective tissue called periosteum, which plays a key role in bone growth and repair.
5. Unlike cancellous bone, compact bone is relatively solid with very few spaces, making it more resistant to bending and fracturing.

Review Questions

• How does the structure of compact bone contribute to its function in the human body?
  • The structure of compact bone is organized into tightly packed osteons that provide maximum strength and support. The concentric rings of mineralized matrix within each osteon allow for efficient load-bearing capabilities. The presence of Haversian canals also facilitates nutrient delivery and waste removal, ensuring that the dense tissue remains healthy and functional. This arrangement allows compact bone to effectively withstand forces applied during daily activities.
• Compare and contrast compact bone with cancellous bone in terms of their structure and functions.
  • Compact bone is dense and forms the outer layer of bones, providing strength and structural integrity. In contrast, cancellous bone is lighter and has a spongy appearance, located primarily at the ends of long bones and in the interior of others. While compact bone helps resist bending and compressive forces, cancellous bone aids in weight reduction and houses red marrow for blood cell production. Together, they contribute to overall skeletal function.
• Evaluate the role of compact bone in the process of bone remodeling and how this impacts overall skeletal health.
  • Compact bone plays a vital role in the process of bone remodeling by serving as a reservoir for calcium and phosphate, which are crucial for maintaining mineral balance in the body. During remodeling, osteoclasts break down old compact bone while osteoblasts build new tissue. This dynamic process helps to repair micro-damage from stressors over time, ensuring that bones remain strong and resilient. Disruptions in this balance can lead to conditions such as osteoporosis, highlighting the importance of healthy compact bone for overall skeletal health.

Related terms

Osteon:

The fundamental functional unit of compact bone, consisting of a central canal surrounded by concentric rings of bone matrix and osteocytes.

Cancellous bone: Also known as trabecular or spongy bone, it is a lighter, less dense type of bone found beneath the outer layer of compact bone, providing support while reducing weight.

Bone remodeling: The ongoing process where old bone tissue is replaced by new bone tissue, involving the coordinated actions of osteoblasts (bone formation) and osteoclasts (bone resorption).