Why are the constellations Ursa Major and Ursa Minor called circumpolar constellations?

Some stars and constellations never rise nor set, and they are called circumpolar ... Constellations in the northern circumpolar sky include Auriga, Camelopardalis, Cassiopeia, Cepheus, Draco, Lynx, Perseus, Ursa Major, and Ursa Minor. These constellations are always visible in the night sky of the Northern Hemisphere.