As Ayurveda is the science from the times of Vedas (because as the sub part of the fourth Veda i.e. Atharvaveda). Its understanding is based on the philosophy of Sankhya (Samkhya darshana). In the theory of Sapta dhatu Ayurveda explains about the formation of the Physical body or Sthula shareera through them.
As it is formed from the two Sanskrit words i.e. Sapta (seven) and Dhatu (which holds the body). It is very commonly used by Ayurveda scholar i.e. “धारणात धातु” which means dhatu are the elements which holds the physical form i.e. physical body. In Ayurveda there are seven fundamental elements that supports and form the basic structure of the body. These seven dhatus are accepted by all the Acharyas (Educators) of Ayurveda, that means this theory with same vocabulary is appreciated by all from the time of vedas. These dhatus are formed at the time of foetus growth by getting the nourishment from the mother. And after the birth of the child; he will prepare his dhatus from the food he consumes.
The Rasa dhatu is the foremost dhatu which is formed inside the body after the digestion and assimilation of food by the help of Rasa agni (fire of Rasa dhatu). It is correlated with Plasma and Lymph many a times. This dhatu after the Paka (assimilation/ digestion) converted into the Rakta dhatu with the help of Rakt agni (fire of Rakta dhatu). It gives the Preerana effect (nourishment) to the body.
This Rakta dhatu is formed from Rasa dhatu with the help of Rakta agni (fire of Rakta dhatu), which is correlated with Blood in todays science. It gives the Jeevana effect (life) to the body.
The Mamsa dhatu is formed from the Rakta dhatu with the help of Mamsa agni (fire of Mamsa dhatu). It gives the Lepan effect (coating effect) to the body and is correlated with the muscles now a days.
This is formed from the Mamsa dhatu with the digestion through Meda agni (fire of Meda dhatu). It helps in the Snehan effect (lubrication) of the body, and is correlated with fat inside the body.
It is formed from the Meda dhatu with the help of Asthi agni (fire of Asthi). It gives Dharana effect (forming the structure) to the body and is correlated with the Bones.
It is formed from the Asthi dhatu with the help of Majja agni (fire of Majja). It helps in the Poorana effect (filling) to the bones because they are hollow in structure, and correlated with the bone marrow.
It is the last dhatu with is formed from Majja dhatu with the help of Shukra agni (fire of Shukra dhatu). It gives the Garbho utapadana effects (reproduction), and is correlated to sexual hormones/ sperm/ ovum.
This Sequence is always accepted by all the Samhita (compendium) of Ayurveda. The main factor in production of any dhatus is there respective Agni. This Agni is the fire which only converts one particular dhatu to another particular dhatu. This Agni/ fire is very much dhatu specific (Sapta dhatu & Sapta agni), they got energy from the main Jatragni (Jatra means the abdominal raeson; Agni present in the abdomen). Acharyas (educators like Charaka And Sushruta) of Ayurveda stated many of different theories in the formation of these Sapta dhatus.
