EVERYDAY SCIENCE

Detailed explanation-1: -Compact bone makes up the outer layer of the bone. Spongy bone is found mostly at the ends of bones and contains red marrow. Bone marrow is found in the center of most bones and has many blood vessels. There are two types of bone marrow: red and yellow.

Detailed explanation-2: -Compact bone consists of closely packed osteons or haversian systems. The osteon consists of a central canal called the osteonic (haversian) canal, which is surrounded by concentric rings (lamellae) of matrix. Between the rings of matrix, the bone cells (osteocytes) are located in spaces called lacunae.

Detailed explanation-3: -Bones are composed of two layers: a tough outer layer and a spongy inner layer. The outer layer, known as cortical or compact bone, is strong and dense. The inner layer, known as trabecular or cancellous bone, features a light network of connective tissue.

Detailed explanation-4: -The periosteum, endosteum and perichondrium are all layers of tissue in and around your bones. The periosteum is the sheath outside your bones that supplies them with blood, nerves and the cells that help them grow and heal. The endosteum is a membrane that lines the center of your bones that contain bone marrow.

Detailed explanation-5: -Compact bone tissue is composed of osteons and forms the external layer of all bones. Spongy bone tissue is composed of trabeculae and forms the inner part of all bones. Four types of cells compose bony tissue: osteocytes, osteoclasts, osteoprogenitor cells, and osteoblasts.