Types of connective tissue
1. Areolar
2. Adipose
3. Fibrous
1. Areolar : It is a pliable, mesh-like tissue with a fluid matrix and functions to cushion and protect body organs.Cells called fibroblasts are widely dispered in this tissue; they are irregular branching cells that secrete strong fibrous proteins and proteoglycans as an extracellular matrix.
It can be found in the skin as well as in places that connect epithelium to other tissues.The areolar tissue is found beneath the dermis layer and is also underneath the epithelial tissue of all the body systems that have external openings.It is also a component of mucus membranes found in the digestive, respiratory, reproductive, and urinary systems.It also surrounds the blood vessels and nerves.
It acts as a packaging tissue holding the internal organs together and in correct placement.It holds organs in place and attaches epithelial tissue to other underlying tissues.
2. Adipose : Adipose tissue, or fat, is an anatomical term for loose connective tissue composed of adipocytes. Its main role is to store energy in the form of fat, although it also cushions and insulates the body. Obesity in animals, including humans, is not dependent on the amount of body weight, but on the amount of body fat—specifically adipose tissue. In mammals, two types of adipose tissue exist: white adipose tissue (WAT) and brown adipose tissue (BAT). Adipose tissue also serves as an important endocrine organ by producing recently-discovered hormones such as leptin, resistin and TNFα.
Adipose tissue is primarily located beneath the skin, but is also found around internal organs. In the integumentary system, which includes the skin, it accumulates in the deepest level, the subcutaneous layer, providing insulation from heat and cold. Around organs, it provides protective padding. It also functions as a reserve of nutrients.
3. Fibrous : fibrous connective tissue (FCT) is a type of connective tissue which has relatively high tensile strength, due to a relatively high concentration of collagenous fibers. Such tissues form ligaments and tendons; the majority of the tissue does not contain living cells, the tissue is primary composed of polysaccharides, proteins, and water.
The cells of fibrous connective tissue are mostly fibroblasts, irregular, branching cells that secrete strong fibrous proteins as an extracellular matrix. The most commonly secreted protein is collagen which represents one-fourth of all vertebrate protein. Collagen is tough and flexible and gives strength to tissue. Elastin fibers are thinner than collagen fibers and are also secreted by fibroblasts. These protein fibers have longer cross-links than collagen fibers, which gives elastin fibers great elasticity
There are several categories of fibrous connective tissue:
* Loose connective tissue supports most epithelia and many organs. It also surrounds blood vessels and nerves. It is also found between muscles
* Dense connective tissue has collagen fibers as its main matrix element.
* Elastic connective tissue is primarily composed of elastin fibers, giving them great elasticity. It appears in the walls of the aorta.
* Reticular connective tissue is composed of interlacing fibers of collagen called reticular fibers. This tissue forms supporting structures for many organs, such as the spleen and thymus.
2007-02-20 03:50:48
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answer #1
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answered by MSK 4
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