Sapta Dhatu

Ayurveda recognizes seven bodily tissues (sapta dhatu) that form the structural and functional basis of the body. In order of formation they are: rasa (plasma and lymph), rakta (red blood cells), mamsa (muscle), meda (adipose), asthi (bone), majja (bone marrow and nervous tissue), and shukra/artava (reproductive tissue).

Each dhatu has a primary function: rasa provides nutrition, affection, and immunity; rakta governs oxygenation and life function; mamsa provides form, movement, and protection; meda provides lubrication and insulation; asthi provides structural support; majja fills bone spaces and governs sensation, learning, and memory; and shukra/artava governs reproduction and produces ojas.

Each dhatu also produces a superior byproduct (upa-dhatu) and an inferior waste (mala). For example, rasa produces lactation and menstruation as upa-dhatus and poshaka kapha as its mala. Bone produces teeth as its upa-dhatu and hair and nails as its mala. The reproductive tissue produces ojas as its supreme byproduct, with no waste.