CONNECTIVE TISSUE PROPER – 1
This is the most common type of connective tissue. Its is distributed throughout the body and composed by several types of resident and transient connective tissue cells as well as by an extracellular matrix.
Its cells are classified into two groups: resident cells, that are regularly present in the tissue and transient cells, that are settled in other tissues and may migrate and exert their functions in the connective tissue. The predominant resident cells in this tissue are the fibroblasts, in addition to macrophages, mast cells, and mesenchymal cells. Transient cells in varying quantities are also common inhabitants of this tissue. Its extracellular matrix is mainly composed of fibers and several kinds of important molecules, such as proteoglycans.
Depending on the relative proportion between cells and extracellular matrix as well as on the organization of its extracellular matrix, the connective tissue proper is classified as:
Loose connective tissue
Dense connective tissue that has two subtypes: a) regular dense connective tissue and b) irregular connective tissue.
Some of its most relevant functions are:
- Support of lining and glandular epithelia
- Support of blood vessels, lymphatic vessels, nerves
- Support of muscles and their components
- Filling spaces within tissues, between tissues, and between organs
- Protection and containment of organs by forming capsules around them
- Containment and isolation of skeletal muscles
- Union of skeletal muscles to bones by the tendons.