Bone tissue has the supporting function and occurs in the bones of the vertebrate skeleton.
It is a rigid fabric thanks to the presence of matrix rich in calcium, phosphorus and magnesium salts. In addition to these elements, matrix is rich in collagen fibers, which provide some flexibility to the bone.
Bones are organs rich in blood vessels. In addition to bone tissue, they have other types of tissue: reticular, adipose, nervous and cartilaginous.
Because they are one innervated and irrigated structure, bones have sensitivity, high metabolism and regenerative capacity.
When a bone is sawn, it is realized that it is formed by two parts: one without cavities, called compact bone, and another with many communicating cavities, called cancellous bone.
This classification is of macroscopic order, because when these parts are observed under the microscope it can be noticed that both are formed by the same histological structure. The microscopic structure of a bone consists of numerous units called Havers systems. Each system has concentric layers of mineralized matrix deposited around a central canal where there are blood vessels and nerves that serve the bone.
The Havers canals communicate with each other, with the medullary cavity, and with the outer surface of the bone through transverse or oblique channels, called perforating channels (Volkmann's channels). The inside of the bones is filled with bone marrow, which can be of two types: yellow, consisting of adipose tissue, and red, which forms blood cells.