Better way to structure XQuery

[Stacy.Ladnier at noaa.gov]

I have the following XQuery:

xquery version="1.0";

let $mydoc :=doc('http://localhost:8080/exist/rest/db/bio.xml')
let $profileType := 'Standard'
let $profileType := if
($mydoc/metadata/idinfo/spdom/bounding/boundalt/altmin or
$mydoc/metadata/idinfo/spdom/bounding/boundalt/altmax) then 'Biological'
else $profileType

return 
   <result>
      {$profileType>
   </result>

This works fine, however, I would like to take the paths and place them
in a sequence (there are potentially 30+ I need to check for). I am new
to XQuery/XPath and unable to figure out the proper way to do this. 

Can anyone let me know how to use two variables, one being the $mydoc
and one being a string ($path :=
'/metadata/idinfo/spdom/bounding/boundalt/altmin') and have it evaluate
as XPath instead of as a string?