Vatta as defined by the name circulates in the whole body. It is also defined as the initiating power of all the functions of the body. It is the main transporter in the body. Vatta is most crucial of all the three doshas and treating it is considered as half of the complete regime. Other two doshas- pitta and kapha are dependent on vatta only for their movement. Vatta controls all the organ systems of the body and help in smooth functioning. Ingestion of food, speech, respiration, digestion and expulsion of waste material in the form of faeces is facilitated by vatta only. Nervous system is also governed by vatta dosha.
Pitta is a fire element and thence is responsible for digestive functions and various other functions which dissipate heat like comprising complexion of the body, etc. Pitta can be defined as controlling the functions those results in exothermic reactions, viz. Digestion, pigmentation, regulation of body temperature, formation of erythroblasts, maintaining vision etc.
Kapha comprises predominantly of water and earth elements. It helps in smooth execution of various functions in the body, viz. Production of digestive juices, lubricating various joints and membranes in the body in the form of synovial fluid and cerebrospinal fluid etc.
Doshas are the principle metabolic forces and they control the physiological processes and psychological behaviour of an individual.