AsclepioA red blood cell's journey in 3D
Blood travels through two circuits joined by the heart, which is why we call it double circulation. In the pulmonary circuit, the right side of the heart…
Explained for every age
For kids (7–11)
Join a red blood cell on its big journey. It goes from the heart to the lungs to pick up oxygen, comes back to the heart and then heads out to deliver it all over your body. It makes a full lap in about a minute!
For teens (12–16)
Blood travels through two circuits joined by the heart, which is why we call it double circulation. In the pulmonary circuit, the right side of the heart sends blood to the lungs to pick up oxygen and drop off carbon dioxide. In the systemic circuit, the left side pushes it out to all the organs. A red blood cell passes through both circuits on every lap.
Pre-Med (17+)
Human circulation is double and complete: two pumps in series (right and left heart), each with an atrium and a ventricle, with no mixing of oxygenated and deoxygenated blood. The pulmonary circulation is low-pressure and the systemic circulation is high-pressure; the double circulation allows blood to be repressurized after passing through the lungs and speeds up O₂ delivery. The erythrocyte carries O₂ bound to hemoglobin and a fraction of the CO₂ (most of it travels as bicarbonate in the plasma). At rest, a full circuit takes on average about 60 s (approximate value).
What you can explore
Pulmonary circulationSystemic circulationCapillary exchangeOxygen loadingRed blood cell life cycleCirculation time
Missions
- The red blood cell's big lap Explorer
- Double circulation Discoverer
- Circuits, exchange and red cell turnover Pre-Med