According to Ayurveda, the human body is composed of Doshas, Dhatus and Malas.
Vata, Pitta and Kapha are the three somatic humours. Though they provide for the whole system, the humours have their separate dominions in the body. The Vata is responsible for the lower part, the Pitta for the middle portion and the Kapha for the upper part. Dosha connotes fault or error. As such the term Tridoshas, which means the three Doshas, is attributed to them because of their disposition to get vitiated due to various reasons. When doshas are in equailibrium, body is said to be in perfect health.
According to the Indian theory of the evolution of the physical world, all matter is made up of the Pancha Maha Bhutas (Five Great Elements). These are air, water, fire, earth and ether. As with everything else, Vata, Pitta and Kapha also originate from the Pancha Maha Bhutas.