The human body is like a complex machine with many parts (organs) that work together to keep us alive. Here is a quick overview of these body systems, which will help you understand how the organs you learn about later fit into the bigger picture. 0:00 Circulatory System 0:34 Respiratory System 1:06 Digestive System 1:44 Nervous System 2:21 Endocrine System 2:57 Muscular System 3:38 Skeletal System 4:14 Integumentary System 4:53 Lymphatic System 5:31 Immune System 6:13 Urinary System 6:46 Reproductive System