Ayurveda is mainly focused in the three great terms viz. Vata, Pitta and Kapha; called Tridosha. These are the great physiological terms so to understand this properly is to understand all about Ayurveda. The general meaning of Vata, Pitta and Kapha may be air, bile and sputum respectively but it’s not that. These terms in Ayurveda has a great significance.
Vata may be understood as nerve force, electro-motor, physical activity or that, which is responsible for motion. It is commonly called air. The root, ‘va’ means to spread. In Western terms, it is the electricity setting the organism into motion, maintaining the equilibrium between Pitta and Kapha (inerts). Vata relates to the nerve-force. It is responsible for all movement in the mind and body. The movement of Vata even regulates the balance of Pitta and Kapha. Pitta relates to internal fire, bile, body heat, digestive enzymes, physio-chemical, biological, metabolic and endocrine systems. It is responsible for digesting the chyle into a protoplasmic substance like sperm and ovum.
Kapha fills the intercellular spaces of the body as connective tissue. Examples of these tissues include mucus, synovial fluid, and tendons. Kapha is responsible for the gross structure of the body (solid and liquid/phlegm-plasma). Each person is made up of a combination of these elements.
Together, the doshas are responsible for catabolic and anabolic metabolism. Catabolism breaks down complex internal bodies, and Vata (air energy) sets this energy free into simpler waste. Anabolism takes food and builds it into more complex bodies. The summit of the metabolic process is protoplasm or essential matter [proteins, carbohydrates, lipids, and inorganic salts]. Lifeless food becomes living protoplasm and is set free as useful energy or excess heat or motion that is emitted from the body. Thus, the purpose of the three doshas is to move the lymph chyle (the by-product of digested foods) throughout the body. This nourishes and builds the body tissues. When any or all of the doshas develop imbalance, the body ceases to be nourished, and disease develops.
The three doshas (Vata, Pitta, Kapha) exist throughout the entire body, in every cell, yet are predominant (their sites of origin) in the colon, small intestine, and stomach, respectively. Some authorities say that Vata primarily resides below the navel, Pitta from the navel to the heart, and Kapha, above the heart.
Vata is also found in (governing) the waist, thighs, ear, bones, and skin. Pitta also governs the navel, sweat, lymph, blood, eye, and skin. Kapha additionally controls the chest, throat, head, bone joints, small intestine, plasma, fat, nose, and tongue.
Finally whatever we do to try to understand these three Tridosha; knowledge is still unsatisfactory. Yes of course we can satisfy our knowledge on Ayurveda but wisdom is still lacking. I love this beauty of Ayurveda.