Loose connective tissue

Areolar tissue, reticular tissue, and adipose tissue are all examples of loose connective tissue, which is a type of connective tissue that includes them all. Loose connective tissue is the most common type of connective tissue in vertebrates, accounting for approximately 80% of all connective tissue. It is responsible for holding organs in place as well as attaching epithelial tissue to other underlying tissues. The formation of telae, such as the tela submucosa and the tela subserosa, which connect the mucous and serous membranes to the muscular layer, is an example of how it functions. It also has a protective layer around the blood vessels and nerves. Fibroblasts are cells that are widely dispersed throughout this tissue; they are irregular branching cells that secrete fibrous proteins and proteoglycans as an extracellular matrix to support the tissue’s structure. The cells of this type of tissue are generally well separated by a gelatinous substance that is primarily composed of collagenous and elastic fibres, with some exceptions.

Structure of Loose Connective Tissues

Composition

• It is a pliable, mesh-like tissue with a fluid matrix that serves to cushion and protect the organs of the body from injury.
• These cells are irregular branching cells with irregular morphology that secrete fibrous proteins and proteoglycans to act as an extracellular matrix. Fibroblasts are widely dispersed throughout this tissue.
• In most cases, the cells of this type of tissue are connected by a gelatinous substance known as ground substance, which is primarily made up of collagenous and elastic fibres and connects the cells together.

Location

Tissue sections from nearly every part of the body have been found to contain this protein. It covers blood vessels and nerves, allowing them to pass through into the small spaces of muscles, tendons, and other tissues with the blood vessels and nerves. It is also possible that it is present in the mediastinal extremities. It is believed that nearly every epithelium rests on a layer of areolar tissue, whose blood vessels supply the epithelium with nutrients and waste removal, as well as a ready supply of infection-fighting leukocytes when necessary. Because there is an abundance of open, fluid-filled space in areolar tissue, leukocytes are able to move freely throughout the tissue and quickly locate and destroy pathogens.

Located beneath the epidermis layer, the areolar tissue can be found in all body systems that have external openings, as well as beneath the epithelial tissue of all other body systems. It makes the skin more elastic and helps it to withstand the pain of being tugged on. Also found in the digestive and respiratory tracts, mucous membranes of the reproductive and urinary systems, glandular stroma, and the hypodermis (underlayer of the skin). It can also be found in the mesentery, which is the tissue that surrounds the intestines.

Fibres

The term “loose connective tissue” refers to the “weave” and type of fibres that make up its constituent tissues. In general, there are three types:

• Collagenous fibres: Collagenous fibres are made of collagen and are composed of bundles of fibrils, which are coils of collagen molecules. Collagenous fibres are a type of protein.
• Elastic fibres are made of the protein elastin, and they have the property of being “stretchable.”
• Reticular fibres: Reticular fibres are made up of one or more types of very thin collagen fibres that are arranged in a reticular pattern. They are responsible for connecting connective tissues to other tissues.

Areolar tissue

Areolar tissue is a type of loose connective tissue that is commonly found in the body (and the most widely distributed type of connective tissue in vertebrates). It was given this name because its fibres are spaced far enough apart to allow plenty of open space for interstitial fluid to pass between them. It is strong enough to bind different types of tissue together while remaining soft enough to allow for flexibility and cushioning to be provided. This tissue is characterised by interlacing, loosely organised fibres, a large number of blood vessels, and a significant amount of empty space filled with interstitial fluid.

Many adjacent epithelial tissues (which are avascular) obtain their nutrients from the interstitial fluid of areolar tissue; the lamina propria is areolar in many parts of the body, including the lungs and liver. Its fibres are arranged in a random pattern and are mostly collagenous, but there are also elastic and reticular fibres in the tissue. Irrespective of its appearance, areolar tissue has a wide range of appearances. It appears as a loose arrangement of collagenous and elastic fibres, scattered cells of various types, abundant ground substance, and numerous blood vessels in many serous membranes. Generally speaking, it is more compact in the skin and mucous membranes, and can be difficult to distinguish from dense irregular connective tissue in these areas.

Function

Areolar connective tissue is responsible for the retention of organs and the attachment of epithelial tissue to other underlying tissues. It also serves as a reservoir of water and salts for the tissues in its immediate vicinity. It is in areolar connective tissue that nearly all cells obtain their nutrients and excrete their wastes.

Conclusion

Connective (supporting) tissue is a type of tissue that is voluminous, strong, and elastic at the same time, and it plays important roles in the human body. It provides mechanical strength, as well as physical and metabolic support, to all of the other types of tissues in the human body.