Ayurveda explains that the very first concept of dhatu covers the function, substance and structure and on the other hand, the concept of mala is explained primarily as a substance. The concept of dosha is not objectifiable as it is taken in terms of materialistic structure or substance. Dosha is understood in terms of its operational dynamics. In Ayurvedic theories these three concepts are given a more expanded definition. The three components of the body are briefly explained here -
Dhatus: These are defined as the retained substances and structures of the body. They are usually translated as body tissues. This particular term implies something, which has structure within the body like that of bones and muscles. All the dhatus do not appear in solid form and nor do they have a structure always, such as in case of blood. Dhatus exist in many forms within the body like solid, semi-solid and liquid. Ayurveda says that the meaning of dhatu is something more precise and inclusive. They are actually those structures and substances that are retained by the body and are always replenished and rejuvenated. Dhatus are like a natural part of the composition of the body. They give the body its physical strength, functions and structural integrity. Importantly, those substances are considered as dhatus as long as they are kept inside the body. Extensive unnatural loss of the dhatus can even cause death. This point signifies the importance of the dhatus.
A total of seven dhatus compose the retainable substances and structures of the body. These seven dhatus are 'Rasa', which is the nutrient fluid forming the basis of blood or 'Rakta', the second dhatu. 'Mamsa' is the third dhatu, it means the muscle tissue. 'Meda' is the fourth dhatu, it is also known as adipose tissue or fat. Fifth dhatu is the 'Asthi' that signifies bone. 'Majja' is the sixth dhatu that implies nerve tissue or bone marrow. Last that is the seventh dhatu is known as 'Shukra', which is the reproductive tissue of the body. The developmental sequence of the dhatus is reflected through the manner how a human foetus matures. Initial stages of the growth of a foetus are characterized by the first dhatus that mainly signify nutrient fluid, muscle tissue and blood. The deeper dhatus that are known as marrow, bones and other subtle forms of reproductive tissues arise a bit later.
Malas: It is the second component of the body. These are those substances that body normally discharges in the entire process of maintaining and creating of dhatus. Malas includes all the substances that are expelled because they are not beneficial for the body's support. It comprises those substances that are separated from the dhatus and eliminated from the body for correcting imbalances. Malas naturally arise as the unusable natural by-products of the digestive process that are closely connected with the formation of the seven dhatus. It is mentioned in Ayurveda that if the malas do not get separated from the body in proper quantity and at appropriate time, their accumulation tend to cause an imbalance, which damages the proper functioning of the dhatus. It is also said that if the wastes are retained in the body for too long that could actually pose a threat to life.
Doshas: They are the last and the most important component of the human body. This component is of vital importance as it is responsible for coordinating and directing all the substances and structures of the body. The 'Theory of the Tridoshas' is considered as really unique in Ayurveda and it actually helps in locating the seeds of any disease. The doshas do not have any obvious material qualities like the dhatus. Knowledge of the doshas actually gives a proper understanding of the functioning and the intelligences that commands the dhatus and the malas of the body.
The three components of the body are responsible for keeping particular things balanced within the body. Ayurveda derives from these essential components of the body what exactly is going on in the body.