The Seven Bodily Tissues - Sapta Dhatus
The dhatus are the basic varieties of tissues which compose the human body. The word “dhatu” comes from a Sanskrit word which means “that which enters into the formation of the body”; the root Daa (dha) means “support, that which bears”.

The primary Dhatus are seven in number, They are:

Sukra dhatu (reproductive tissues) Majja dhatu (bone marrow and nervous tissues) Asthi dhatu (bone) Meda dhatu (fatty tissues) Mamsa dhatu (muscle tissues) Rakta dhatu (formed blood cells) Rasa dhatu (plasma)

The most unique feature of Ayurvedic histology (concept of tissue formation) is that each human tissue is formed from the previous tissue in ascending order of complexity. Thus when food is ingested it is digested until, in the small intestines, it becomes a liquidy, chyme-like material known in Ayurveda as ahara rasa, or food essence. With the help of ahara rasagni (each dhatu has its own agni), this ahara rasa is converted into Rasa dhatu (blood plasma)--the first and most simple tissue.
Now, Rasa dhatu catalyzed by Rasagni is transformed into Rakta dhatu (formed blood cells), the second fundamental bodily tissue. Rakta dhatu in turn, with the help of raktagni, becomes mamsa dhatu (muscle), and so on.

Sukra dhatu (reproductive tissues)
Majja dhatu (bone marrow and nervous tissues)
Asthi dhatu (bone)
Meda dhaut (fatty tissues)
Mamsa dhatu (muscle tissues)
Rakta dhatu (formed blood cells)
Rasa dhatu (plasma)

Together, the dhatus and upadhatus make up the physical bulk of the body. The upa dhatus include hair, nails, ligaments, etc.; they are important structurally but usually are not implicated in disease conditions of the body.
Each dhatu consists of countless infinitesimal paramanus (cells) which are units of structure and function. Each paramanu contains innumerable suksma srotas (channels, pores) through which it receives nutrients and subtle energies and eliminates waste materials. Because dhatus are saturated with pores, the human body can also be said to be filled with pores (srotomaya). The srotas of each dhatu are unique in their structure and function and in the materials which move through them. The state of health of each dhatu as well as its relative vriddhi/kshaya (excess/deficiency; increase/decrease) is assessed by the physician.

Waste Materials - Malas

As a consequence of foods which we take into our bodies from the external world and the normal biological processes which take place internally, we generate different kinds of waste materials, or malas, which must be excreted. Ayurveda generally recognizes two kinds of malas:

ahara mala or wastes from food
dhatu mala or wastes from the tissues

The ahara malas include feces (purisha), urine (mutra), and sweat (sveda). These are the three main malas. The dhatu malas include the various secretions of the nose, eyes, ears; lactic acid, carbon dioxide, and other metabolites of cellular respiration; exfoliated hair, skin, and nails. Although these are all waste products, they serve a role in maintaining health as long as they are normal in their quantity (pramana), qualities (gunas), and function (karma). However, if the malas become abnormal in some regard (i.e. increased or decreased) they become a factor in creating disease. When the dhatus and malas become unbalanced they are called dushyas (soiled). The malas are composed predominantly of different elements. Feces is composed mainly of earth element; urine, mainly water and fire; sweat, primarily water. Of course all five elements are contained in every mala.

The following chart summarizes the effects of increased (vriddhi) or decreased (ksaya) malas:

The three malas
Mala	Vriddhi (increase)	Ksaya (decrease)
Feces (purisha) Mahabhuta: earth	Heaviness Flatulence Abdominal discomfort (generalized)	Bloating Abdominal pain (mid) Low back pain Weakness Asthma Osteoarthritis Hypokalemia Hypocalcemia
Urine (mutra) Mahabhuta: water and fire	Urinary frequency Bladder dysfunction Urinary tract infections	Reduced urine Chronic thirst Renal stones Abdominal pain (lower)
Sweat (sveda) Mahabhuta : water	Perspires easily Fungal dermatoses Low body temperature Constipation Body odor Itching Constipation	Decreased perspiration Dry skin Burning sensations High body temperature