Structure Of Bone Tissue - Bone Structure Anatomy - Components Of Bones

0:00The bones in your body are made up of an extraordinarily complex connective tissue,

0:03that's structure matches its function. It is comprised of cells, fibers, and extracellular

0:09material, or matrix. Let's start by looking at a diagram of bone tissue. There are two main types

0:15of bone tissue, compact bone and cancellous or spongy bone. Compact bone surrounds the spongy

0:22bone tissue and it has a unique appearance. These cylinder shaped structures are called

0:27osteons, or haversian systems. in the middle of these osteons is a central haversian canal that

0:33runs lengthwise through the bone, and it houses nerves and blood vessels that supply the bone

0:38with nutrients. The cylinder shaped layers of the osteons are called concentric lamellae.

0:44The lamellae are composed of calcified matrix, and this matrix is comprised of inorganic salts

0:50and organic material. The inorganic matrix is made up of rock like crystals of calcium

0:56and phosphate called hydroxyapatite crystals. Calcium carbonate, magnesium, sodium, sulfate, and

1:03fluoride are also found in bone material. The organic material is comprised of collagenous

1:09fibers and a gel like ground substance containing protein and polysaccharides. The ground substance

1:15is important in providing support and adhesion between cellular and fibrous elements. There is

1:21also a circumferential lamellae that runs along the periosteum, which covers the outside of bones,

1:26and along the endosteum, which lines the inner spongy bone tissue. Interstitial lamellae are

1:33located between osteons. Lacunae are the small spaces in bone tissue where mature bone cells

1:39called osteocytes are imprisoned. These cells are responsible for maintaining the bone matrix.

1:44Canaliculi are small canals that extend in many directions from the lacunae, connecting to other

1:51lacunae in the central canal. They provide for intercellular communication and a passageway

1:57for the delivery of nutrients to the osteocyte cells. There are also transverse or Volkmann canals,

2:04which connect central canals to one another, and these canals also house nerves and blood vessels.

2:09Now for spongy bone tissue. Spongy bone has no osteons, as it has a lattice like appearance of crisscrossing

2:16branches called trabeculae. The trabeculae are comprised of endosteum, surrounding parallel

2:22lamellae, which are composed of bone matrix and osteocytes in lacunae, with canaliculi extending

2:29out from the lacunae. Some of the canaliculi open onto the surface of the trabeculae. Like in compact

2:36bone tissue, the canaliculi provide a passageway for nutrients to reach the osteocytes cells. The

2:42formation or lattice like look of spongy bone allows it to distribute any stress or pressure

2:47applied to it throughout the entire framework. And that be the basics on the structure of bone tissue.