Dhatus: Bodily Tissues
Ayurveda has identified seven constituent tissues whereby the body both lives and dies. These tissues are called dhatus. Like doshas, dhatus are formed from the five elements – space, air, fire, water, and earth. The Sapta (seven) Dhatu (tissues) elements form the pillars of the body that form the means of nourishment and growth while providing support to the body as well as the mind.
With the help of the digestive fire, the dhatus form the body’s protective biological system. In other words, they nourish and defend the internal immune system. If one dhatu is defective, each successive dhatu is affected, thereby triggering a chain reaction of impairment throughout the entire tissue system.
The concentric formation of dhatus occurs through the ingestion of food substances. Infinitely well expressed by Charaka, the use of naturally healthy foods is essential to the quality of nutrients responsible for sustaining the dhatus: “The availability and consumption of a wholesome diet are essential to promote the healthy growth of a person; likewise, indulgence in unwholesome foods promotes diseases.” Equally relevant is the recognition that mental unrest or a negative outlook contaminates even the most wholesome foods once these have been ingested.
Through an enormously sophisticated process of chemical reactions (main digestive fire called jatharagni)*, spurred by both the energy in the food and the energy vibrations of bodily tissues and mental thoughts, the nutrient called ahara rasa is produced.
The main digestive fire lies in the umbilicus region called jatharagni(macroscopic- can be seen as hydrochloric acid,pancreatic juice etc ). Every dhatu has its own digestive fire called dhatwa-agni (microscpic-on the tissue and cellular level, cannot be seen), which is a subtle part of the jatharagni and is totally dependent on the jatharagni. So if the jatharagni of a person is strong and well working all the dhatwagnis will be working properly and the all the tissue formation (each cell) will be of superior quality and vice the versa.
The nutrient, once absorbed into the digestive tract, is synthesized by the rasa- dhatu digestive fire i.e rasadhatwa-agni to form the first of seven tissues, rasa dhatu. This tissue, a milky, sticky, cold chyle resembling the quanlities of Kapha, is the body’s plasma tissue and derives its existence from the water element. The proper conversion of the primary nutrient, ahara rasa, into plasma is dependent upon the quality of the foods, the state of mind, health of bodily prana (prana vayu), the main digestive fire i.e JATHARAGNI and the tissues digestive fire (rasadhatwa-agni). In wholesome conditions, these factors contribute to the production of plentiful rasa. In unhealthy conditions, they contribute more to the production of wastes in the form of mucus i.e ‘ama’, rather than to the production of healthy plasma.
Each of the six subsequent dhatus is fed by the previous dhatu. Once rasa tissue is formed,
The nutrients are refined through a process by raktadhatwa-agni and transported to form blood tissue, rakta dhatu. Again, if the nutrients quality is defective, the production of bodily waste in form of bile is produced at expense of healthy blood tissue. The main universal element comprising blood is fire. Rakta (blood) Dhatu – Regarded as the basic of life, it not only nourishes the body tissues, but provides physical strength and colour to the body.
Not surprisingly, then, once the hemoglobin of the blood is nourished, the nutrients are further refined by mamsadhatwa-agni , to provide the fuel necessary to produce muscle tissue, mamsa dhatu. Masma Dhatu – The muscle tissues main function is to provide physical strength and support for the meda dhatu. Muscle tissue’s dominant element is earth, the most matter-like element of the five elements from which the dhatus derive their form. The body’s muscle tissue shares earth’s nature of matter. Next in the dhatu nourishment is the fat tissue from medadhatwa-agni, called medas dhatu which is pervaded by water element. It’s main function is lubricating the entire body system.
The bone and cartilage tissue, (asthi dhatu) from the asthidhatwa-agni which is pervaded by the elements air and space is next in the dhatu nourishment lineage. Ashti Dhatu – Comprising of bone tissues, including cartilages, its main function is to give support to the majja dhatu and provide support to the masma dhatu.
The continuously refined nutrients are then transported and converted by majjadhatwa-agni to the tissue comprising the body’s red and white bone marrow, majja dhatu. Majja Dhatu – Denoting the yellow and red bone marrow tissue, its main function is to fill up the ashti and give fullness to the body.
Finally, the refined nutrient remaining after all these dhatus have been fed replenishes the sperm and ovum tissues, shukra and artava respectively by their shukradhatwa-agni. This last dhatu, once formed, is fed by the subtle essences of the nutrients refined through the synthesis of all the previous dhatus. It is the subtle pervasive essence remaining in the body before it becomes the material for procreation. If this dhatu is contaminated or not properly formed, due to pollution of the nutrients, the new life formed from the union of sperm and ovum is usually adversely affected in some way or other.
Since the dhatus support and derive energy from each other, affecting one can influence others. For instance, interference in the manufacture of the plasma affects the quality of the blood, which in turn affects the muscle. As mentioned earlier each tissue type has its own agni (digestive fire- dhatwa-agni) which determines metabolic changes in the tissues and forms by-products*, which are either used in the body or excreted. Menstural periods for example are a by-product of rasa. The tissues are also governed by the three doshas, and any imbalance in them also causes imbalances in dhatus.
* see the chart above (table no 9)