Understanding Bone Structure: Essential Components Revealed

1. Skeletal Tissue Structure of Bones

2. Parts of a Bone • A typical long bone consists of: • Diaphysis • Epiphyses • Metaphyes • Articular Cartilage • Periosteum • Medullary Cavity • Endosteum

3. Diaphysis • The bone’s shaft or body • The long, cylindrical, main portion of a bone

4. Epiphyses • The distal and proximal ends of a bone • Each long bone has a distal epiphysis and a proximal epiphysis

5. Metaphyses • The regions in mature bone where the epiphysis and diaphysis meet. • The regions in growing bone that contains the epiphyseal plate (growth plate) • Epiphyseal Plate – a layer of hyaline cartilage that allows the diaphysis to grow in length. When this growth stops, the epiphyseal plate is replaced by bone resulting in a bony structure known as the epiphyseal line.

6. Articular Cartilage • A thin layer of hyaline cartilage covering the part of the epiphyses where the bone forms a joint with another bone. • Reduces friction and absorbs shock • Does not have a perichondrium, so repair of damage is limited

7. Periosteum • Tough sheath of dense irregular connective tissue that surrounds the bone surface wherever it is not covered by articular cartilage. • Contains bone forming cells that allow the bone to grow in diameter • Protects the bone, assists in fracture repair, helps nourish bone tissue and serves as an attachment point for ligaments and tendons

8. Medullary Cavity • Marrow Cavity • Space within the diaphysis that contains fatty yellow bone marrow in adults. • Young bones contain mostly red bone marrow

9. Endosteum • Thin membrane that lines the medullary cavity. It contains a single layer of bone forming cells