Arteriole. Light micrograph of a longitudinal section through an arteriole blood vessel (across centre) in the capsule of a lymph node. Arterioles carry blood from the arteries to the network of capillaries that supply oxygen and nutrients to the body tissues. Lymph nodes are small swellings of lymphoid tissue found at intervals along the lymphatic system. Each node is surrounded by a capsule of collagenous connective tissue which provides it with structural support. Lymph nodes filter foreign particles from the lymph and produce white blood cells (lymphocytes). Trichrome blue stain. Magnification unknown.