Click any part of the heart to find out what it does.
72bpm
Fig. 1
Fig. 2
Cut open, drag to rotate, scroll to zoom
ClosedHalfWide open
Deoxygenated blood (low in oxygen)Oxygenated blood (rich in oxygen)Heart muscle (carries neither)
Remember: the heart is drawn as if it is facing you, so the right side of the heart (and the right lung) appear on the left of the screen.
Select a part to zoom in. Fit shows the whole heart again.
How to use this
Explore: click any structure on the diagram to read what it is and what it does.
Blood flow: watch blood travel round the double circulation, or step through one lap a stage at a time.
Pump it yourself: nothing moves until you press the button. Squeeze both atria, squeeze both ventricles, push the blood out, then let the ventricles relax: four stages, and each one shuts or opens the valves it is actually responsible for.
Heartbeat: one beat in slow motion, with a live ECG. The five stages are written out in full so they stay readable; click one to freeze the heart there.
Fitness lab: change the activity level and calculate cardiac output. You can enter your own pulse too.
Quiz: three rounds: find the part, multiple choice, and put the stages in order.
Switch between the cross-section and the 3D model above the diagram. Drag the 3D heart to spin it, scroll or pinch to zoom, and use the slider to cut it open.
On a phone, select a part of the cross-section to zoom in on it, select Fit to see the whole heart again, and use the list of structures under the diagram.
Use the Labels button to pin names onto the diagram, Coronary to bring in the heart’s own blood supply, and Sound for the “lub dub” heart sounds, which play while the heart is beating on the Heartbeat and Fitness lab tabs.
If your device is set to reduce motion, the heart holds still. Use Next stage, the step-by-step buttons and each press of the pump button to move it, or press Play to start it yourself.
You can also press Tab and Enter to move around the diagram with a keyboard. On the 3D model, the ←→↑↓ keys spin it and +− zoom.
Never done this before? Work along the tabs from left to right:
look round in Explore, watch the lap in Blood flow, drive it yourself in
Pump it yourself, then slow one beat down in Heartbeat, and finish with the Quiz.
Built for the Singapore syllabus, Sec 1 to Sec 4/5: Lower Secondary Science through to O-Level Biology. Every fact here is simplified for learning, so a real heart is more detailed than this.