Bones are the rigid organs that make up the skeletal system of vertebrates. They provide support and protection for the body, as well as serving as the anchor for muscles to produce movement. Additionally, bones store minerals such as calcium and phosphorus, and they contain bone marrow, where bloodcells are produced.
Structure of Bone
Bones are composed of two types of tissue: compact bone and spongy bone. Compact bone is the dense, hard outer layer that provides strength, while spongy bone is a porous, honeycomb-like inner structure that contains bone marrow. The outer surface of bones is covered by a membrane called the periosteum, which contains blood vessels and nerves.
Osteoblasts: These cells are responsible for bone formation by secreting the matrix that eventually becomes mineralized.
Osteocytes: Once the bone matrix is mineralized, some osteoblasts become trapped within it and become osteocytes, which help maintain the bone structure.
Osteoclasts: These cells are involved in the breakdown and resorption of bone tissue, allowing for bone remodeling.
Bone Growth and Development
Bones grow and develop through a process called ossification, which can occur through two methods:
Intramembranous ossification: This process occurs in flat bones, where bone tissue forms within a membrane.
Endochondral ossification: This process occurs in long bones, where bone tissue forms within a cartilage model.
Understanding the structure, function, and development of bones is crucial for comprehending the human skeletal system and its role in overall health and movement.
Reading Standards for Literacy in Science and Technical Subjects
Craft and Structure
Determine the meaning of symbols, key terms, and other domain-specific words and phrases as they are used in a specific scientific or technical context relevant to grades 6-8 texts and topics.