Connective tissue. Coloured scanning electron micrograph (SEM) of bundles of collagen fibres forming part of the connective tissue. Connective tissue provides structural and metabolic support for other tissues and organs throughout the body. Collagen, the most common fibrous protein in connective tissue, is resistant and inflexible. While elastic fibres are made from elastin, another protein, which allows the recovery of tissue shape after deformation or stretching. Collagen and elastin are both produced by fibroblast cells within the connective tissue. Magnification unknown.