Srotāmsi
The Rivers and Systems of the Body

A Srotas (translated from Sanskrit-river/stream) is a channel through which nutrients, tissues (dhātu-s), wastes (mala),  and sensory information move and flow. There are many srotāmsi (pl.) in the body; single cells, capillaries, nādis, etc.. Smaller srotas can make up larger srotas, such as the larger māha srotas (the gastro-intestinal tract).
 
Each srotas has a sroto mūla (root), a sroto mārga (passage) and sroto mukha (mouth or opening). There can be disturbances to the flow in the srotas such as blockage, deficient or excessive flow, and false passage (the content of the srotas goes the wrong way).

The first three srotas are for receiving (Prāna, Anna/food, Ambu/liquids). The next seven correspond to the seven dhātus and are for nourishmant (Rasa, Rakta, Māmsa, Meda, Asthi, Majjā, Shukra). The last three are expelling wastes (mala) from the system (Sveda/sweat, Purisha/feces, Mūtra/urine). In the female there are also two more srotas, Ārtava and Sthanya, which regulate menstrual flow and breast milk respectively. The mind has a srotas called Mano, within which every thought and emotion has a smaller srotas.

The srotāmsi are usually referenced singularly as 'vaha srotas'. For example: Prāna vaha srotas, Anna vaha srotas, etc..
Vaha translates as 'carrying, bearing'. Therefore, Anna vaha srotas is the 'food carrying river' and so forth for the other srotāmsi, respectively.