internal organ vs intestine

internal organ

noun
  • An organ, such as the heart or colon, that is entirely within the confines of the body. 

intestine

noun
  • One of certain subdivisions of this part of the alimentary canal, such as the small or large intestine in human beings. 

  • The alimentary canal of an animal through which food passes after having passed all stomachs. 

adj
  • Domestic; taking place within a given country or region. 

How often have the words internal organ and intestine occurred in a corpus of books? (source: Google Ngram Viewer )