Composition and Physicochemical Properties
In histological nomenclature, this group traditionally includes two main varieties: cartilage tissue and bone tissue.
The fundamental physicochemical property that unites these tissue types and distinguishes them from other structures in the body is the hardness of the extracellular matrix. This characteristic is provided by the specific chemical composition of the matrix, namely, a high content of inorganic mineral components.
However, the degree of mineralization varies drastically depending on the specific type of tissue:
- In cartilage tissue, the concentration of mineral salts is relatively low, ranging within 4–7%. This allows cartilage to retain a certain degree of flexibility and elasticity.
- In bone tissue, the level of mineralization reaches its maximum, accounting for about 70%. It is this massive accumulation of inorganic substances that grants bone its exceptional hardness and strength.
Functional Profile
The range of functions performed by skeletal tissues in the body is exceptionally broad. For ease of study, they are typically divided into three major categories:
- Mechanical functions. These tissues serve as the structural base of the musculoskeletal apparatus. Furthermore, they form rigid cages that provide reliable physical protection for vital internal organs against external trauma.
- Metabolic functions. Skeletal tissues act as a major mineral reservoir. They take a very active part in systemic mineral metabolism, primarily regulating calcium and phosphate balance in the body.
- Morphogenetic function. This role is particularly prominent during embryonic development (embryogenesis). In the early stages of organism formation, cartilage tissue acts as a primary "model" or template upon which the vast majority of our skeletal bones subsequently develop.
Embryonic Origin
Histogenesis (the process of tissue formation) of all skeletal tissues shares a common embryonic root. Their sole developmental source is mesenchyme, the embryonic connective tissue.
In turn, the mesenchymal cells that give rise to future cartilages and bones originate from specific embryonic structures—somites and splanchnotomes. This strict pathway of differentiation ensures the proper establishment of the entire supporting framework of the developing organism.