What the body does
Physiology in the same cited graph as the anatomy: which structures take part in respiration, digestion and circulation, and in what order.
Processes are nodes too
A process has its own id class and lives in the same graph as the structures it involves, so "what takes part in respiration" is the same kind of question as "what is part of the thorax" and is answered the same way.
The coverage is honest
Only a handful of processes are recorded per species today. The page says how many rather than implying the physiology layer is complete.
Questions
Why so few processes?
Physiology is curated by hand rather than ingested from an ontology, so it grows slowly and every step carries a citation.