The sub-ordinators of dhatus is called as Upadhatu.Up means sub and dhatu means tissues.
शरीर धारणात धातवः /
Dhatus means which furnishes the body.Dhatus are the building unit of body as it is responsible for physical composition of body.They form the structure of body.
While upadhatus are the sub-tissues or secondary tissues in the body and responsible for some important functions in body.
Upadhatus are formed from their specific dhatus.They get their nourishment from their parent dhatus.Upadhatus perform some important functions in body and help in body maintainance.
Updhatus are supporting blocks of main building unit i.e Dhatus.
Asthi(bone),majja(bone marrow) and sukra(semen) does not posses their upadhatus.
रसात स्तन्यं ततो रक्तम अस्रूक कंडरा सिरा:/
मांसात वसा त्वचा षट च मेदस: स्नायू संभवः // च चि १५/१७
|Rasa Dhatu||Stanya (breast milk) & Aartava (menstrual blood,ovum)|
|Rakta Dhatu||Siras(blood vessels,vein)& Kandaras (tendons)|
|Mamsa Dhatu||Vasa (muscles fat) & Twak (skin)|
|Meda Dhatu||Snayu (ligaments,nerves) & sandhis (joints)|
Difference between Dhatus and Upadhatus-
Dhatus provides nourishment to their subsequent dhatus like rasa dhatu provides nourishment to rakta dhatu but Upadhatus don’t.
Dhatus are responsible for the formation of Dhatu malas(waste products) during the cycle formation of dhatus but Upadhatus don’t.
Importance of Upadhatus-
Each Upadhatu has their specific role.Like Stanya is responsible for lactation,while for the menstrual cycle maintainance and reproduction aartava is essential.Siras helps in circulation while kanadar and snayu is responsible for holding the body tissues together and helps in the body support.Vasa provide lubrication and twak covers the whole body and provide protection to the body.It also responsible for beautification of body.Sandhis responsible for body movements and locomotion.
Any defects in the formation of dhatu leads to vitiation of upadhatu which leads to formation of disease hence it is very important to maintain the equilibrium of dhatu and Upadhatus.