Physiology of Bone and bone minerals, deficiencies and treatments

Introduction

Bones are passive organs of locomotion. They are tough, rigid and yellowish-white. It is a variety of tissue mesenchymal having a high affinity for the calcium salts. These bones give attachment to the muscles, organs protect fragile (the nervous system, lungs and heart) and involved in the regulation phosphate balance.

Function of Bone

Bone function is to maintain good works bones and the skeleton, but also to provide the body the calcium it needs to function normally.

Bone cells

Osteoclasts are giant multinucleated cells (4-20 nuclei). Usually they are in contact with the calcified bone surface and within gaps resulting from their own resorptive activity. Main enzyme is acid phosphatase. Osteoclasts are motile cells. They surround the part of the bone that has resorbed. Their life expectancy is 2 to 20 days.

Osteoblasts are large cells with basophilic cytoplasm. Actively synthesizing osteoblasts are cubical or cylindrical cells with thin branches. Main enzyme osteoblasts are alkaline phosphatase (ALP). Active osteoblasts cover 2-8% of the surface of the bone, inactive (dormant cells) - 80-92%, forming a continuous cell layer near the sinus medullary canal. The main function of osteoblasts is protein synthesis. They form osteoid plates by deposition of collagen fibers and proteoglycans. After 8-9 days of the final thickness of this layer is 12 microns. After a ten-ripening begins mineralization of osteoblasts from the opposite side, the front moves in the direction of mineralization of osteoblasts. At the end of the cycle every ten osteoblast immured as osteocyte. The rest remain on the surface of osteoblasts as inactive. They are involved in the metabolism of bone tissue (Brookes, 90).

Osteocytes are inactive metabolic bone cells. Osteocytes originate from osteoblasts, immured in own bone matrix, which later calcific. These cells have many long processes to communicate with other cellular processes of osteocytes. They form a network of thin tubules that spread throughout the bone matrix. The main role of osteocytes is intracellular and extracellular transport of nutrients and minerals.

Types of Bone

Cortical Bone

The compact bone or lamellar bone or Haversian forms the walls of the shaft or cortex. This bone is composed of Haversian systems. Each system or osteon formed:

1.A central channel (Haversian canal) containing vascularized connective tissue, of osteoblasts and osteoclasts;

2.Of bone lamellae in concentric and have between which the osteocytes.

This type of bone is denser than other types and represents 80 percent of the weight of the skeleton of a human being. It is mainly present in the portion of the shaft of long bones of a person, such as the bones found in the arms and legs. Furthermore, the outer shell found around the spongy bone, at the end of the joints consists of cortical bone.

Trabecular Bone

The trabeculae of bone tissue are formed by lamellae, distinct layers of fibers and bone cells held together by collagen fibers. The lamellae have a microscopic structure common to all types of lamellar bone tissue; in the spongy bone tissue they are arranged in a disorderly manner forming cavities inside occupied by ...