Long bones

Definition

Long bones are a type of bone characterized by their elongated shape, typically longer than they are wide, and consist of a shaft (diaphysis) and two ends (epiphyses). These bones play a crucial role in supporting the weight of the body and facilitating movement by acting as levers for muscles. They are primarily found in the limbs and are essential for locomotion and overall skeletal integrity.

5 Must Know Facts For Your Next Test

1. Long bones include major bones such as the femur, humerus, tibia, and radius, which are critical for movement and structural support.
2. These bones are composed of both compact bone, which provides strength, and spongy bone, which helps reduce weight while maintaining structural integrity.
3. The growth of long bones occurs at the epiphyseal plates during childhood and adolescence, which allows for increases in length as a person grows.
4. Long bones have a rich blood supply due to their vascular structure, aiding in nutrient delivery and waste removal for bone health.
5. Fractures in long bones can have significant implications for mobility and may require medical intervention such as casting or surgery for healing.

Review Questions

• How do long bones contribute to the overall function of the skeletal system?
  • Long bones are essential for the skeletal system as they provide structural support, facilitate movement, and act as levers for muscle action. Their elongated shape allows them to withstand forces exerted during physical activities while maintaining mobility. The arrangement of compact and spongy bone within these structures also contributes to their strength-to-weight ratio, enabling efficient movement without excessive mass.
• Discuss the significance of the diaphysis and epiphysis in the structure and function of long bones.
  • The diaphysis serves as the main supportive shaft of a long bone, providing strength through its dense compact bone structure. In contrast, the epiphysis at each end is crucial for articulation with other bones at joints, as they are typically covered with articular cartilage to minimize friction. Together, these components not only give long bones their characteristic shape but also ensure proper functionality during movement and weight-bearing activities.
• Evaluate how injuries to long bones can affect mobility and overall health.
  • Injuries to long bones, such as fractures or breaks, can significantly impair mobility by limiting the range of motion and stability at joints. The healing process may involve extended periods of immobilization or rehabilitation, affecting physical activity levels and overall health. Additionally, severe injuries can lead to complications like malunion or nonunion, where the bone fails to heal properly, potentially resulting in chronic pain or disability that impacts daily life.

Related terms

Diaphysis: The central shaft of a long bone, which is primarily composed of compact bone and provides strength and support.

Epiphysis: The ends of a long bone, which are often covered with articular cartilage and play a key role in joint movement and stability.

Medullary cavity: The hollow interior of the diaphysis in long bones that contains bone marrow, which is involved in blood cell production.