Question: where does the blood in the hepatic portal vein come from
[{'answer': 'gastrointestinal tract', 'provenance': [{'wikipedia_id': '235642', 'title': 'Portal vein', 'start_paragraph_id': 1, 'start_character': 85, 'end_paragraph_id': 1, 'end_character': 107, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'gallbladder', 'provenance': [{'wikipedia_id': '235642', 'title': 'Portal vein', 'start_paragraph_id': 1, 'start_character': 109, 'end_paragraph_id': 1, 'end_character': 120, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'pancreas', 'provenance': [{'wikipedia_id': '235642', 'title': 'Portal vein', 'start_paragraph_id': 1, 'start_character': 122, 'end_paragraph_id': 1, 'end_character': 130, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'spleen', 'provenance': [{'wikipedia_id': '235642', 'title': 'Portal vein', 'start_paragraph_id': 1, 'start_character': 135, 'end_paragraph_id': 1, 'end_character': 141, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '235642', 'title': 'Portal vein', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 421, 'bleu_score': 0.970795021215021, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14199089528883864939}, 'section': 'Section::::Abstract.'}]}]