I thought you all would like to know who did what in a division, so I looked it up here: http://bleach.wikia.com/wiki/Gotei_13. This is the Gotei 13 list of specialties the Divisions are meant for! So here they are:
Division Division Specialty
1st--> No special duties have been noted for the 1st Division, other than their Captain being the Captain-Commander of the Gotei 13.
2nd--> No special duties have been noted for the 2nd Division, other than the 2nd Division being directly tied in with the Onmitsukidō, each of the top 5 seated officers is in charge of a certain division of the latter. For example the 3rd Seat is in charge of the Detention Unit.
3rd--> No special duties have been noted for the 3rd Division.
4th--> The 4th Division is the medical/supply division. They are responsible for both treating the injured and doing most manual labor such as cleaning Seireitei. Because of this, they have keys to most of the buildings and know the underground sewer system well. According to various members of the 11th Division, 4th Division members are rather weak at combat instead using their power to heal. The 4th Division is further divided into teams that have specific assigned jobs.
5th--> They are the messenger squad of the Gotei 13, and many of its members appear to be skilled in Kidō.
6th--> No special duties have been noted for the 6th division.
7th--> No special duties have been noted for the 7th Division.
8th--> No special duties have been noted for the 8th Division.
9th--> The 9th Division is known to be in charge of the Seireitei news magazine. All the Lieutenants of the Divisions of Gotei 13 hand in their report to them.
10th--> No special duties have been noted for the 10th Division.
11th--> The Eleventh Division is the melee combat Division with a specialization in swords-only combat, forgoing the other Shinigami arts. It is mentioned that it is tradition for the current Kenpachi, the title held by the best swordsman in Soul Society, to hold the position of Eleventh Division Captain.[5] The current captain Kenpachi Zaraki is known for his thirst for fighting.
12th--> Other than the 12th Division's connection to the Shinigami Research and Development Institute, no special duties have been noted for the 12th Division. Members are tasked with research and collection of data and samples, and the Captain is the President of the R&D Institute.
13th--> The 13th division seems to be in charge of the Communications department in the Soul Society. It also seems to assume Earth's protection against hollows.
Kidō Corps--> The Kidō Corps is responsible for opening the senkaimon, the gate between the human world and Soul Society.
