When adapted to television, the anime "Bleach" was broken into 16 story arcs. However, not all of the plotlines within each arc were originally in the published mangas that the show is based on.
The arc titles are: "Agent of the Shinigami", "Soul Society: The Sneak Entry", "Soul Society: The Rescue", "The Bount", "Bount Assault on Soul Society", "Arrancar: The Arrival", "Arrancar: The Hueco Mundo Sneak Entry", "Arrancar: The Fierce Fight", "The New Captain Shūsuke Amagai", "Arrancar vs. Shinigami", "The Past", "Arrancar: Decisive Battle of Karakura", "Zanpakutō Unknown Tales", "Arrancar: Downfall", "Gotei 13 Invading Army" and "The Lost Substitute Shinigami".
These are translated from the original language, Japanese. They are also known by the names given in the English adaptation, which are different. These arcs cover 366 episodes and are usually about 20 episodes each, though much longer and shorter ones exist.
The reason not all the anime's arcs are in the original manga is that the show goes through material quicker than the manga. Therefore, anime-only stories are created to allow the manga's author, Tite Kubo, time to publish more stories. In addition two TV specials, called "Original Video Animations" in Japan, have been created. The first is called "Memories in the Rain", and the second is titled "The Sealed Sword Frenzy".