Fibroblast cell. Confocal light micrograph of a human fibroblast cell crawling over a glass surface. The cell has been fluorescently stained to reveal the filament proteins actin (red) and vincutin (green) within the cytoplasm. Actin filaments interact with other proteins producing cell movement, while vincutin is present at points of attachment betweeen the cell and the surface. Fibroblasts are found in connective tissue. They produce collagen, the main structural protein in the body. A confocal microscope detects light only from the focal point of its objective lens, allowing thin sections of an intact specimen to be imaged. Magnification: x2000 when printed 10cm wide.