histology vs microanatomy

histology

noun
  • The study of the microscopic structure, chemical composition and function of the tissue or tissue systems of plants and animals. 

microanatomy

noun
  • Microscopic anatomy: the anatomy of minuscule structures, at microscopic scale. 

  • Synonym of histology. 

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