How the Circulatory System Works | A Red Blood Cell's Round Trip

How does blood reach a working muscle and return to the heart? Follow one red blood cell through the arteries, leg capillaries, veins, lungs, and heart again. This journey shows how the two circuits connect, why oxygen crosses a capillary wall while the red cell stays inside the vessel, and how walking muscles and venous valves help blood return from the leg. The highlighted cell follows one example route; blood branches to many organs in parallel. Continue exploring Related episode: How the Respiratory System Works    • How the Respiratory System Works | From Br...   Human Body Explained playlist:    • Human Body Explained | Trace the Science   Explore all Trace the Science episodes:    • Science Explained | All Episodes — Trace t...   Chapters 00:00 A red cell's round trip 00:16 Two circuits, one continuous flow 01:01 Leaving the left ventricle 01:43 Branching arteries and capillaries 02:32 Oxygen crosses the capillary wall 03:19 How blood returns from the leg 04:05 Through the right heart and lungs 04:49 Back to the starting chamber 05:38 Why the return works Sources NHLBI — How Blood Flows through the Heart: https://www.nhlbi.nih.gov/health/hear... OpenStax — Heart Anatomy: https://openstax.org/books/anatomy-an... OpenStax — Blood Flow, Blood Pressure, and Resistance: https://openstax.org/books/anatomy-an... OpenStax — Capillary Exchange: https://openstax.org/books/anatomy-an... #CirculatorySystem #BloodFlow #ScienceExplained