The court of original jurisdiction is the first court that hears a case. appellate courts hear cases on appeal from lower courts. although the supreme court functions primarily as an appellate court, it is the courts of original jurisdiction in certain kinds of cases. what are those?

Article III, Section II, US Constitution:  

In all Cases affecting Ambassadors, other public Ministers and Consuls, and those in which a State shall be Party, the supreme Court shall have original Jurisdiction. In all the other Cases before mentioned, the supreme Court shall have appellate Jurisdiction, both as to Law and Fact, with such Exceptions, and under such Regulations as the Congress shall make.

Explanation: