Connective tissue (CT) is a kind of animal tissue that supports, connects, or separates different types of tissues and organs of the body. It is one of the four general classes of animal tissues—the others of which are epithelial, muscle, and nervous tissues. Connective tissue is found everywhere in the body except the central nervous system.
All CT has three main components: ground substances, fibers and cells. All are immersed in the body fluids.
Connective tissue can be broadly subdivided into connective tissue proper, special connective tissue, and series of other, less classifiable types of connective tissues. Connective tissue proper consists of loose connective tissue and dense connective tissue (which is further subdivided into dense regular and dense irregular connective tissues.) Special connective tissue consists of reticular connective tissue, adipose tissue, cartilage, bone, and blood. Other kinds of connective tissues include fibrous, elastic, and lymphoid connective tissues.
Fibroblasts are the cells responsible for the production of some CT.
Characteristics of CT:
- Cells are spread through an extracellular fluid.
- Ground substance - A clear, colorless, and viscous fluid containing glycosaminoglycans and proteoglycans to fix the bodywater and the collagen fibers in the intercellular spaces. Ground substance slows the spread of pathogens.
- Fibers. Not all types of CT are fibrous. Examples of non-fibrous CT include adipose tissue and blood. Adipose tissue gives "mechanical cushioning" to our body, among other functions. Although there is no dense collagen network in adipose tissue, groups of adipose cells are kept together by collagen fibers and collagen sheets in order to keep fat tissue under compression in place (for example, the sole of the foot). The matrix of blood is plasma.
- Both the ground substance and proteins (fibers) create the matrix for CT.
Types of fibers:
|Collagenous fibers||Bind bones and other tissues to each other||Alpha polypeptide chains||tendon, ligament, skin, cornea, cartilage, bone, blood vessels, gut, and intervertebral disc.|
|Elastic fibers||Allow organs like arteries and lungs to recoil||elastic microfibril & elastin||extracellular matrix|
|Reticular fibers||Form a scaffolding for other cells||Type-III collagen||liver, bone marrow, lymphatic organs|
- Storage of energy
- Protection of organs
- Provision of structural framework for the body
- Connection of body tissues
- Connection of epithelial tissues to muscle fiber.
- Supply of hormones all over the body
- Nutritional support to epithelium
- Site of defense reactions
It is estimated that 1 out of 10 people have a Connective Tissue Disorder. Various CT in CT.
Staining of connective tissue
For microscopic viewing, the majority of the CT staining techniques color tissue fibers in contrasting shades. Collagen may be differentially stained by any of the following techniques:
- Van Gieson's stain
- Masson's Trichrome stain
- Mallory's Aniline Blue stain
- Azocarmine stain
- Krajian's Aniline Blue stain
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