Long Bones

Definition

Long bones are a category of bones characterized by their elongated shape, typically being longer than they are wide. They play a crucial role in movement and support, serving as levers that facilitate actions like walking, running, and lifting. Long bones also house bone marrow, which is essential for producing blood cells, and they contribute to the overall structure and strength of the skeletal system.

5 Must Know Facts For Your Next Test

1. Long bones are found primarily in the limbs, including the femur (thigh bone), humerus (upper arm bone), and tibia (shin bone).
2. These bones are vital for weight-bearing activities due to their structural design, which allows them to withstand significant forces.
3. The growth of long bones occurs at the growth plates, which close after puberty when a person reaches full height.
4. Long bones are composed of both compact and spongy bone tissue; compact bone provides strength while spongy bone helps reduce weight without sacrificing strength.
5. The hollow center of long bones contains marrow, which is essential for the production of red blood cells, white blood cells, and platelets.

Review Questions

• How do long bones contribute to movement and stability in the human body?
  • Long bones act as levers that provide mechanical advantage during movement. When muscles contract, they pull on the long bones at their attachment points, allowing for efficient movement such as walking or lifting. Their elongated shape also helps distribute weight evenly across joints, contributing to stability and balance during various physical activities.
• What is the significance of the growth plates in long bones, particularly during adolescence?
  • Growth plates are critical for the elongation of long bones during childhood and adolescence. They contain cartilage that allows for continued bone growth until adulthood. Once growth is complete, these plates close, indicating that a person has reached their maximum height. This process is influenced by hormonal changes during puberty, emphasizing the connection between growth plates and overall development.
• Evaluate the roles of both compact and spongy bone tissue in long bones and how they relate to overall skeletal function.
  • Compact bone tissue provides strength and rigidity to long bones, allowing them to endure external forces without fracturing. It forms the dense outer layer that protects inner structures. On the other hand, spongy bone tissue reduces weight while maintaining structural integrity by creating a network of trabecular struts. This combination of both tissue types allows long bones to effectively support body weight and facilitate movement while remaining lightweight enough for mobility.

Related terms

Epiphysis: The end part of a long bone, which is initially separated from the main bone by a growth plate and is involved in the formation of joints.

Diaphysis: The main or central shaft of a long bone, providing structural support and containing the medullary cavity, which stores bone marrow.

Osteocytes: Mature bone cells that maintain the bone matrix and communicate with other bone cells to regulate bone health and mineral content.