Dextrins are short portions which include the branch points of polysaccharides.  Oligosaccharides are usually 3 to 8 glucose units long, but may be longer. Oligosaccharides are important in attaching to lipids and proteins in the cell membrane to form a glycocalyx. These oligosaccharides are composed of  monosaccharides other than glucose (see below) and can be quite variable in structure. This gives them uniqueness which is part of the cells identity.