Continue nursing fibrous tissue (6)
I believe the answer is:
tendon
'fibrous tissue' is the definition.
(tendon is a kind of fibrous tissue)
'continue nursing' is the wordplay.
I cannot quite understand how this works, but
'continue' could be 'on' (I've seen this in other clues) and 'on' is found within the answer.
The remaining letters 'tend' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for tendon that I've seen before include "Strong band of tissue connecting muscles" , "common subject of strain" , "Tissue connecting a muscle with its bony attachment" , "personal connecting link" , "horse's hamstring" .)