The following videos from Khan Academy will provide you with a fundamental understanding of the gastrointestinal system.  The first video will provide you with a basic understanding of the GI tract.  The second video will introduce you to the crucial role the liver plays in our health.  For more extensive information, please visit the Khan Academy Health & Medicine section where you will find a comprehensive playlist of videos, worksheets, and quizzes to help you to better understand your own anatomy and physiology.