These are considered to be a life force and are therefore given importance in the diagnosis and treatment of disease. These are carriers of different powers according to vital organs as defined by the Unani physicians. The seat of Arwa as per the Unani concept is the place of the skull from where these forces emerge, namely -

a) Rooh-e-Nafania (mental faculties) The 'Brain' is the seat of this vital force. This is the center of sensation and movement (Quwat e Hissia and Quwat e Muharika)

b) Rooh-e-Haivania: 'Heart' is the seat of this vital force. This is the center of vital life.

c) Rooh-e-Tabiyah: 'Liver' is the seat for this vital force. This is the center of nutrition.

There is a 4th faculty for preserving the race, which is located in the testes in men and the ovaries in females. This is known as Rooh-e-Tanasuliya.