Initially, Senators were appointed by state legislators. There are now 100 Senators. So while the House provides representation according to population, the Senate provides representation according to region. This tends to redistribute power from more populous states to less populous states. Alaska has two Senators representing approximately 600,000 citizens.
Representatives face election three times as often as Senators.
In sum, the two Houses are elected in dramatically different ways. The president and vice president are selected through a national election every four years. The President nominates candidates for the Supreme Court, which must then be approved by the Senate. The governors, and state legislatures, are selected through statewide elections. Because the members of each institution are selected in different ways, they tend to represent different interests in society.