Loose connective tissue is the most common type of connective tissue in vertebrates. It holds organs in place and attaches epithelial tissue to other underlying tissues. It also surrounds the blood vessels and nerves. 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. The cells of this type of tissue are generally separated by quite some distance by a gel-like gelatinous substance primarily made up of collagenous and elastic fibers. Connective tissue is any type of biological tissue with an extensive extracellular matrix and often serves to support, bind together, and protect organs. ... In biology, an organ (Latin: organum, instrument, tool) is a group of tissues, which perform a specific function or group of functions. ... In zootomy, epithelium is a tissue composed of a layer of cells. ... The arterial system The blood vessels are part of the circulatory system and function to transport blood throughout the body. ... Jump to: navigation, search A nerve is an enclosed, cable-like bundle of nerve fibers or axons, which includes the glia that ensheath the axons in myelin. ... A fibroblast is a cell that makes the structural fibers and ground substance of connective tissue. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Proteoglycans represent a special class of glycoprotein that are heavily glycosylated. ...

Loose connective tissue is named based on the "weave" and type of its constituent fibers. There are three main types:

• Collagenous fibers: collagenous fibers are made of collagen and consist of bundles of fibrils that are coils of collagen molecules.
• Elastic fibers: elastic fibers are made of elastin and are "stretchable."
• Reticular fibers: reticular fibers consist of one or more types of very thin collagen fibers. They join connective tissues to other tissues..