Meda is the forth dhatu. It is similar to the adipose tissue. It serves the purpose of connective tissue. Because of its fat content, it also provides lubrication, which helps in smooth movement of organs, especially the visceral organs.
According to Charak, a noted ayurvedic scholar, snayu (aponeurosis, tendons) are the upadhatu of meda. Snayu are the thicker and denser of the deep fasciae that cover, invest, and form the terminations and attachments of various muscles and differ from tendons in being broad, flat, and thin.
Sweda (sweat) is the mala of meda dhatu.
Sweat is produced as a waste product at the time of production of meda dhatu. Sweating is an active process, distinct from perspiration, which is simply evaporation of almost pure water from the surface of the skin. Sweating is one of the principal means of regulating the temperature of the body.
Asthi (bone) literally means which does not get destroyed. The main function of asthi is dharan (to support). Upa Dhatu of asth dgatu are danta (teeth) and itís mala are roma (hair) and Nakha (nails).
Main function Majja dhatu (bone marrow) is puran (filling). It is also considered as one of the four maha sneha (major olients). The mala of majja dhatu are the excrement found in the eye, skin, etc.
Shukra dhatu is the seventh dhatu. The function of shukra dhatu is garbhotpadan (reproduction). The process of regeneration is carried out at the cellular level. All the cells in the body are replaced by new cells at a regular interval. Shukra dahtu is responsible for this regeneration at cellular level.