Portal triads occupy each corner of the lobule: portal vein (largest struct), hepatic artery (smallest of the three), bile duct (lined with cuboidal epith) and lymphatic vessels (nerves and capillaries may be found here as well) surrounded by a sheath of connective tissue (collagen type III – reticular fibers)
http://en.wikipedia.org/wiki/Portal_triad
http://d3jonline.tripod.com/21-Gastr...d_Pancreas.htm