From Season 2 (1970-71).
Segments: The Senator (Hal Holbrook)
The [New] Doctors (E.G. Marshall, David Hartman, John Saxon)
The Lawyers (Burl Ives, Joseph Campanella, James Farentino)
Theme Music: Dave Grusin
Main Title Design: Wayne Fitzgerald
Despite low ratings, "The Senator" won 5 Emmy awards, including Best Drama series.
(Update: "The Senator" is scheduled to be released on DVD June 16, 2015)
Leslie Nielsen and Hari Rhodes starred in the segment "The Protectors" in season 1. The Protectors was replaced by The Senator, which also lasted just one season.
The Lawyers (created by Roy Huggins) lasted three seasons. The New Doctors (co-created by Richard H. Landau, Paul Mason and Steven Bochco and co-produced by Raymond Burr's production company) lasted for four seasons.