Dhatus, or bodily tissues according to Ayurveda.
The word dhatu is derived from the verb ’dha’ which means to hold and thus dhatus are responsible for the sustenance of the life process and can be broadly compared to the basic tissues of the body. They are the direct result of the digestive process.
They are seven in number:
- Rasa – The nutrient fluid of blood plasma
- Rakta – Blood
- Mamsa – Muscular tissue
- Meda – adipose tissue, or body fat
- Asthi – osseous tissue, or connective tissue
- Majja – bone marrow
- Sukra – reproductive, or regenerative tissue
AYURVEDA says that each human tissue is formed from the previous tissue in ascending order of complexity. Each tissue type has its own Agni (Fire), which determines metabolic changes in the tissues. So when food is ingested, it is digested until, in the small intestines, it becomes a liquid material known in Ayurveda as ‘ahara rasa’, or nutritive fluid. With the help of ‘ahara rasagni’ (each dhatu has its own specific metabolic fire) this ahara rasa is taken to the heart through action of Saman vayu and is converted into Rasa dhatu (nutrient fluid or blood plasma) – the first and most simple tissue, within 24 hrs.
Now, Rasa dhatu metabolized by Rasagni is transformed into Rakta dhatu (formed blood cells), the second fundamental bodily tissue. Rakta dhatu in turn, with the help of raktagni, becomes mamsa dhatu (muscle); and similarly the formation of majja, asthi and shukra dhatu takes place.
When a dhatu or tissue is being formed from the ‘Food juice or essence ’, it goes through a phase of conversion that results in the generation of a multitude of by – products such as stool, menstrual fluid, mucus, sweat, hair, and more.
All of this makes up the physical bulk of the body. Dhatus have an inherent tendency to get vitiated or diseased hence they are called dushya. In the disease process first the Doshas get impaired and then they in turn impair the Dhatus. In contrast to doshas, the dushya have no tendency to vitiate other factor of body. They are only a passive component of disease where as the doshas are active participants and perpetrators of disease.