Connective Tissue is a form of fibrous tissue .. It is one of the four types of tissue in traditional classifications (the others being epithelial , muscle, and nervous tissue).

Collagen is the main protein of connective tissue in animals and the most abundant protein in mammals, making up about 25% of the total protein content.

Not to be confused with muscle fibers

There are three types of fibrous tissue:

• Collagenous fibers

• Elastic fibers

• Reticular fibers

Characteristics of Connective tissue:

• Cells are separated

• Matrix - non-living material for the nourishing of cells

• Fibers

Connective tissues have mechanical characteristics of soft tissue. They aid in major packing material, organ framework, provide lubrication, and in the passage of blood vessels and nerves.

Various connective tissue conditions have been identified; these can be both inherited and environmental.

• Marfan syndrome - a genetic disease causing abnormal fibrillin.

• Scurvy - caused by a dietary deficiency in vitamin C, leading to abnormal collagen.

• Ehlers-Danlos syndrome - deficient type III collagen- a genetic disease causing progressive deterioration of collagens, with different EDS types affecting different sites in the body, such as joints, heart valves, organ walls, arterial walls, etc.

• Loeys-Dietz syndrome - a genetic disease related to Marfan syndrome, with an emphasis on vascular deterioration.

• Pseudoxanthoma elasticum - an autosomal recessive hereditary disease, caused by calcification and fragmentation of elastic fibres, affecting the skin, the eyes and the cardiovascular system.

• Systemic lupus erythematosus - a chronic, multisystem, inflammatory disorder of probable autoimmune etiology, occurring predominantly in young women.

• Osteogenesis imperfecta (brittle bone disease) - caused by insufficient production of good quality collagen to produce healthy, strong bones.

• Fibrodysplasia ossificans progressiva - disease of the connective tissue, caused by a defective gene which turns connective tissue into bone.

• Spontaneous pneumothorax - collapsed lung, believed to be related to subtle abnormalities in connective tissue.

• Sarcoma - a neoplastic process originating within connective tissue.

For microscopic viewing, the majority of the connective tissue 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

• Encyclopaedia Britannica, Connective Tissue

• Overview at kumc.edu

• Connective tissue atlas at uiowa.edu