• 21 parts
  • Checked September 2026

Heart Diagram

The human heart cut open from the front, with arrows showing how blood flows through it.

Heart Diagram

Name Date

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
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Write the name of each numbered part.Answer key

  1. Right atrium
  2. Left atrium
  3. Right ventricle
  4. Left ventricle
  5. Aorta
  6. Superior vena cava
  7. Inferior vena cava
  8. Pulmonary trunk
  9. Pulmonary arteries
  10. Pulmonary veins
  11. Tricuspid valve
  12. Mitral valve (bicuspid valve)
  13. Pulmonary valve
  14. Aortic valve
  15. Septum (interventricular septum)
  16. Myocardium (heart wall)
  17. Apex
  18. Chordae tendineae
  19. Papillary muscles
  20. Blood low in oxygen (deoxygenated)
  21. Blood rich in oxygen (oxygenated)

Drawn for this site by script, 2026-09-26. Licence: own work.

Each numbered ring is a button. Use the arrow keys to move between them and Enter to choose. Names are read out in Study, and once a part is answered.

Next step Next: the digestive system, mouth to anus

All 21 parts on the diagram

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Start here: 9 main parts 9

  1. Right atrium Receives blood low in oxygen from the body.
  2. Left atrium Receives blood rich in oxygen from the lungs.
  3. Right ventricle Pumps blood to the lungs through the pulmonary trunk.
  4. Left ventricle Pumps blood to the whole body through the aorta.
  5. Aorta Carries oxygen-rich blood, left ventricle to body. The largest artery.
  6. Superior vena cava Brings blood from the upper body into the right atrium.
  7. Pulmonary trunk Carries oxygen-poor blood out of the right ventricle toward the lungs.
  8. Tricuspid valve Between the right atrium and right ventricle; it has three cusps.
  9. Mitral valve (bicuspid valve) Between left atrium and left ventricle, with two cusps.

Valves and cords 3

  1. Pulmonary valve At the pulmonary trunk's base; stops blood flowing back.
  2. Aortic valve At the aorta's base. Stops blood flowing back into the left ventricle.
  3. Chordae tendineae Cords that tie the valve cusps to the papillary muscles.

The great vessels 3

  1. Inferior vena cava Brings blood from the lower body into the right atrium.
  2. Pulmonary arteries Right and left branches of the pulmonary trunk, one to each lung.
  3. Pulmonary veins Bring oxygen-rich blood from the lungs into the left atrium.

Walls, septum and apex 4

  1. Septum (interventricular septum) The thick wall that separates the right and left ventricles.
  2. Myocardium (heart wall) The heart muscle, the heart wall's thick middle layer.
  3. Apex The rounded tip of the heart, pointing down and to the left.
  4. Papillary muscles Muscles in the ventricle walls that hold the chordae tendineae.

Blood flow 2

  1. Blood low in oxygen (deoxygenated) Body, then right atrium, right ventricle and pulmonary arteries to the lungs.
  2. Blood rich in oxygen (oxygenated) Lungs, then left atrium, left ventricle and aorta to the body.

How this list was compiled: Read 2026-09-26. Wikipedia, Heart, https://en.wikipedia.org/wiki/Heart : the four chambers; the interventricular septum; the wall's three layers including the myocardium; the tricuspid and mitral (bicuspid) valves tied by chordae tendineae to papillary muscles; the pulmonary valve at the base of the pulmonary artery and the aortic valve at the base of the aorta; the superior and inferior venae cavae, pulmonary trunk and arteries, pulmonary veins and aorta; blood low in oxygen through the right side to the lungs and oxygen-rich blood through the left side to the body. Gray's Anatomy (1918), 4b The Heart, https://www.bartleby.com/107/138.html : the same chambers, the ventricular septum, the tricuspid and bicuspid or mitral valves, the pulmonary and aortic semilunar valves, chordae tendineae, papillary muscles, the four pulmonary veins, the venae cavae and the apex. Licence: own work

The drawing: Drawn for this site by script, 2026-09-26. Own work, nothing traced. Licence: own work

How it works

A labeled diagram of the human heart, cut open from the front, with the path of blood through it beside it. The heart's right side is on your left, as in every textbook. Start with the 9 main parts, then the valves, vessels and walls.

Read the full guide

Chambers and valves

The heart has four chambers: two atria on top that receive blood and two ventricles below that pump it. The tricuspid valve sits between the right atrium and ventricle, the mitral valve between the left pair. Chordae tendineae tie both to papillary muscles.

How blood flows

Blood low in oxygen enters the right atrium from the venae cavae, passes to the right ventricle and leaves through the pulmonary valve to the lungs. Oxygen-rich blood returns by the pulmonary veins to the left atrium and left ventricle, then leaves through the aortic valve into the aorta.

  • On a heart diagram, left and right are the body's own: the right atrium and ventricle are on the viewer's left.

Questions and answers

What are the 4 chambers of the heart?

The right atrium, right ventricle, left atrium and left ventricle. The atria on top receive blood; the ventricles below pump it out.

What are the 4 valves of the heart?

The tricuspid valve and the mitral (bicuspid) valve between the atria and ventricles, and the pulmonary and aortic valves where blood leaves the ventricles.

What is the order of blood flow through the heart?

Body, venae cavae, right atrium, tricuspid valve, right ventricle, pulmonary valve, pulmonary arteries to the lungs, pulmonary veins, left atrium, mitral valve, left ventricle, aortic valve, aorta and back to the body.

Why is the left ventricle wall thicker?

It pumps blood to the whole body through the aorta, while the right ventricle pumps only to the nearby lungs.

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