Anatomy and physiology
Follow the blood.
Trace how blood moves through the heart, lungs, and body. Try the six-question challenge, or watch the captioned walkthrough first.
Explore
One circuit, two pumps
Choose a stop or play the path. This map follows normal adult blood flow.
To the lungs
The right heart receives blood from the body
Blood enters the right atrium, crosses the tricuspid valve into the right ventricle, then passes through the pulmonary valve on its way to the lungs.
Show the full route and vessel rule
- Pulmonary circuit: Right ventricle → pulmonary valve → pulmonary trunk and arteries → lung capillaries → pulmonary veins → left atrium.
- Systemic circuit: Left ventricle → aortic valve → aorta and systemic arteries → tissue capillaries → systemic veins → right atrium.
Arteries carry blood away from the heart. Veins carry blood toward it. The pulmonary arteries carry blood lower in oxygen to the lungs, and the pulmonary veins return blood higher in oxygen.
Practice
Circulation challenge
Pick an answer to see the reasoning. Take another run whenever you want.
Watch the full circuit
A 42-second captioned walkthrough of how blood moves through the heart, lungs, and body.
Read and watch
Go deeper into the chambers, valves and two circuits.
- NHLBI · How blood flows through the heart: includes a valve animation.
- OpenStax Anatomy and Physiology 2e · Circulatory pathways: includes labeled circulation diagrams.
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