The study of the forms of the parts of speech  (Morphology)  is the Anatomy of a language.  

The study of functions (Syntax) is the Physiology of a language.

Example of the way both are applied in this course:

They said they had done everything that was necessary.

The analysis of the parts of speech would classify "they" as a pronoun of the 3rd person plural, "said" as the Past tense, Indicative mood of a verb, "that" as a relative pronoun, etc.

The analysis of the syntax would distinguish the main clause, a noun clause that serves as the direct object of the main verb, and a relative clause.  The internal syntax of each clause would recognize its subject, the kind of verb (linking or predicative verb), the predicate nominative if the former, a direct object (if present) of the latter if it is a transitive verb, etc.

    main clause       indirect statement           relative clause

    [They said] (they had done everything) (that was necessary).