Hyaline cartilage. Light micrograph of a section through hyaline cartilage in the knee joint of a foetus. This semi-rigid connective tissue is composed of many chondrocytes (cartilage cells, pale purple). These synthesize an extracellular matrix (dark purple) of proteoglycans, collagen and water that keeps them apart from each other in spaces known as lacunae. Hyaline cartilage is strong but compressible due to its high water content. It reduces friction between the bones in the knee joint as they move against each other. Toluidine blue stain. Magnification: x130 at 35mm size.