Leadership in the Senate
*The Vice President of the United States is the President of the Senate. This makes them the highest-ranking official in the Senate.
*The President Pro Tempore (or, "president for a time") is the second-highest-ranking official, but they are the highest-ranking member. Usually, this is also the most senior senator in the majority party. When the Vice President is not present, the President Pro Tempore presides over Senate sessions.
*The majority and minority leaders are elected by their party to be their voice on the Senate floor.
*Majority and minority whips are assistants to the majority and minority leaders.
*The President Pro Tempore (or, "president for a time") is the second-highest-ranking official, but they are the highest-ranking member. Usually, this is also the most senior senator in the majority party. When the Vice President is not present, the President Pro Tempore presides over Senate sessions.
*The majority and minority leaders are elected by their party to be their voice on the Senate floor.
*Majority and minority whips are assistants to the majority and minority leaders.
Leadership in the House
*The Speaker of the House is the highest-ranking official of the House of Representatives, and is elected by the members of the House. However, on a regular basis, other members of the House preside over debates, not the Speaker. In addition to leading the House and the majority party, the Speaker is still the Representative for their district, and also performs administrative functions.
*The majority and minority leaders are elected by their party to be their voice on the House floor.
*Majority and minority whips are assistants to the majority and minority leaders.
*The majority and minority leaders are elected by their party to be their voice on the House floor.
*Majority and minority whips are assistants to the majority and minority leaders.
This information was obtained from http://answers.usa.gov/