Dosha means that which darkens, soils or causes things to decay. Vata is composed of ether and air. It is the most important of the three Doshas as it governs and provides the motivating force for the other two Doshas. It is the kinetic energy in the body and is the force which directs nerve impulses, circulation, respiration and elimination. It governs all bodily movements.
Pitta is biological fire.
It digests and cooks things in the body. It is responsible for all the metabolic and chemical transformations in the body. It is responsible for digestion of food, eyesight, body temperature, intellect and skin colouration. Kapha is a combination of water and fire. It holds things together, providing cohesiveness.