The Heart
The heart has four chambers and valves to keep blood flowing one way.
About this topic
The heart is a muscular pump with four chambers: two atria receive blood and two ventricles pump it out. The right side sends deoxygenated blood to the lungs, and the left side, with a thicker wall, pumps oxygenated blood to the body. Valves keep flow one-way, producing the "lub-dub" sound.
The pacemaker (SAN) sets the rhythm. Coronary arteries supply the heart muscle, and blockages cause heart attacks. Resting heart rate is about 60–100 beats per minute.
Blood enters the right atrium, passes to the right ventricle and goes to the lungs through the pulmonary artery; it returns through the pulmonary vein to the left atrium, then the left ventricle and out through the aorta. Valves prevent backflow, and the lub-dub sound is the valves closing. The left ventricle wall is thicker because it pumps blood around the whole body.
The heart's own muscle is fed by the coronary arteries; if one is blocked, a heart attack results. The natural pacemaker, the sinoatrial node, sets the rhythm of about 70 beats per minute at rest. Artificial pacemakers and stents are common treatments. A frequent mistake is to label the diagram as seen from the front: the left side of the heart is drawn on the right side of the page.
Key ideas
- Two atria, two ventricles
- Right side pumps to lungs
- Left side pumps to body
Quick check
Use cases: where The Heart helps
- Homework: review the key idea behind The Heart before you start a problem set.
- Exam revision: use the quick check to test whether you can recall The Heart without notes.
- Visual learning: play with the interactive lab to see how The Heart changes when you adjust its inputs.
- Teaching a friend: explain The Heart in your own words, then compare your version with the key ideas.
Biology underpins medicine, farming, conservation and biotechnology.
Frequently asked questions
What is The Heart?
The heart has four chambers and valves to keep blood flowing one way.
What will I learn in The Heart?
Two atria, two ventricles. Right side pumps to lungs. Left side pumps to body.
Is The Heart part of Biology?
Yes. It is one of 150 Biology topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the The Heart lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study The Heart?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.