Some fumes enter all old parts of the gut (9)

I believe the answer is:

mesentera

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'old parts of the gut' is the definition.
I don't know anything about this answer so I can't tell whether it can be defined by this definition.

'some fumes enter all' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'MESENTERA' is hidden in the letters of 'fumes enter all'.

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I've seen this clue in The Guardian.

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