Muscles and digestive passage, for example, digest! (8)
I believe the answer is:
abstract
'digest' is the definition.
(both can mean a summary)
'muscles and digestive passage for example' is the wordplay.
'muscles' becomes 'abs' (I've seen this before).
'and' says to put letters next to each other.
'digestive passage for example' becomes 'tract' (digestive tract).
'abs'+'tract'='ABSTRACT'
(Other definitions for abstract that I've seen before include "Conceptual" , "Nick" , "Steal" , "a work of modern art" , "Brats act in non-concrete way" .)