gastrointestinal sphincter
http://purl.obolibrary.org/obo/UBERON_0011185
http://purl.obolibrary.org/obo/UBERON_0005409
http://purl.obolibrary.org/obo/UBERON_0004590
http://purl.obolibrary.org/obo/UBERON_0013765