Connective Tissue

Its main functions are to provide support and fill spaces between tissues, as well as nourish them.

There are special types of connective tissue, each with a specific function. This varies mainly according to the composition of the matrix and the type of cells present.

Types of Connective Tissue

The classification of different connective tissues can be done according to the material and the type of cells that compose it.

The extracellular matrix , which is the substance between cells, has a variable consistency. It can be: gelatinous (loose and dense connective tissue), liquid (blood), flexible (cartilaginous) or rigid (bone).

Thus, it can be divided into connective tissue itself and connective tissues with special properties, namely: adipose, cartilaginous, bone and blood.

Connective Tissue Properly Said

This tissue, as the name suggests, is the typical connecting tissue . It acts to support and fill the tissues and, in this way, helps them stay together, structuring the organs.

Its extracellular matrix is ​​abundant, composed of a gelatinous part (hyaluronate polysaccharide) and three types of protein fibers: collagen, elastic and reticular.

There are two subtypes of connective tissue itself, classified according to the amount of matrix present, they are:

Loose Connective Tissue

It consists of little extracellular matrix , with many cells and few fibers.

This makes the tissue flexible and not very resistant to mechanical pressure. Some cells are resident, such as fibroblasts and macrophages, and others are transient, such as lymphocytes, neutrophils, and eosinophils.

It is found throughout the body, surrounding organs. In addition, it serves as a passage for blood vessels, thus being important in the nutrition of tissues.

Dense Connective Tissue

It has a large amount of extracellular matrix , with a predominance of collagen fibers, arranged without much organization. There are few cells present, including fibroblasts .

It is found below the epithelium, in the dermis , providing resistance to mechanical pressures, thanks to its many fibers. It is also found in tendons .

Adipose Connective Tissue

It is a type of connective tissue with special properties. Its function is to store energy and also to protect against cold and impacts.

It consists of little extracellular matrix , with a considerable amount of reticular fibers and many special cells, adipocytes , which accumulate fat.

Cartilaginous Connective Tissue

It is composed of a large amount of extracellular matrix, however, it is more rigid in this tissue than in the connective tissue itself. This occurs due to the presence of glycosaminoglycans associated with proteins, in addition to thin collagen fibers.

In cartilage, which is made up of this tissue, chondrocytes are present , cells that are housed within gaps in the matrix.

Due to its special consistency, cartilaginous tissue supports different regions of the body, but with a certain degree of flexibility.

Bone Connective Tissue

It is a more rigid tissue, present in the bones and responsible for support and movement.

It is composed of an abundant extracellular matrix , rich in collagen fibers and special molecules (proteoglycans and glycoproteins). The matrix is ​​calcified by the deposition of crystals (formed from calcium phosphate) on the fibers.

The special tissue cell, the osteocyte , resides within gaps in the rigid matrix. It is a mature cell that originates from osteoblasts , young bone cells.

Blood Connective Tissue

It is a special tissue whose matrix is ​​in a liquid state . This substance is called plasma , and it contains blood cells: red blood cells (erythrocytes) and white blood cells (leukocytes) and platelets (cell fragments).

Hematopoietic or hemocytopoietic tissue is responsible for the formation of blood cells and blood components. It is present in the bone marrow, located inside some bones.

Functions

Each type of connective tissue has specific types of cells and its extracellular matrix contains different molecules and fibers that determine its function.

• Fills spaces between different tissues and structures;
• It participates in the nutrition of cells in other tissues that do not have vascularization, since it facilitates the diffusion of nutrients, as well as gases, between the blood and the tissues;
• Energy reserve in fat cells;
• It acts in the body’s defense through its cells;
• Produces blood cells in the bone marrow.