The periosteum contains blood vessels, nerves, and lymphatic vessels that nourish compact bone. The outer surface of the bone is covered with a fibrous membrane called the periosteum (peri – = “around” or “surrounding”). The medullary cavity has a delicate membranous lining called the endosteum (end- = “inside” oste- = “bone”), where bone growth, repair, and remodeling occur. When the bone stops growing in early adulthood (approximately 18–21 years), the cartilage is replaced by osseous tissue and the epiphyseal plate becomes an epiphyseal line. Each epiphysis meets the diaphysis at the metaphysis, the narrow area that contains the epiphyseal plate (growth plate), a layer of hyaline (transparent) cartilage in a growing bone. Red marrow fills the spaces in the spongy bone. The wider section at each end of the bone is called the epiphysis (plural = epiphyses), which is filled with spongy bone. Compact bone is dense and forms the outer layer of all your bones.Īn adult skeleton is made up of 206 bones, which come in several different shapes and sizes.A typical long bone shows the gross anatomical characteristics of bone. Spongy bone is lightweight and made up of a mesh of needle-like pieces of bone with large spaces between them. Red bone marrow is a soft tissue that produces blood cells and yellow bone marrow is a store for fat.īone can either be spongy or compact.
Running along the centre of long bones, such as your femur (thigh bone), is a cavity filled with bone marrow. A thin membrane called the periosteum covers the surface of your bones. These are held together by a framework of hard, non-living material containing calcium and phosphorous. Your bones contain blood vessels, nerve cells and living bone cells known as osteocytes. Despite appearing dry and lifeless, your bones are a hive of activity. They protect your delicate internal organs and act as a storehouse for minerals, such as calcium.
Your bones are strong enough to support your weight, but light enough to allow movement. Two types of bone: Dense compact bone and lightweight spongy bone Bone marrow: Red marrow makes blood cells.
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