Heart and Blood Vessel Basics

If you know how a healthy heart works, you can better understand what's going on in your heart when something's wrong. And that knowledge can give you more confidence when talking with your doctor about your medical condition or treatment options.

We've included lots of illustrations, animations, and interactive activities in this section to help you:

Speak with confidence.
Look for "Hear This Word" links to hear medical terms pronounced.

Understand how a healthy heart works.
Look for animations that show how the different parts of your heart work—both on their own and together.

Keep heart problems straight.
See common heart problems illustrated, animated, and plainly explained.

Explore the Heart

Intro to the Heart
Learn about your heart's role in keeping your body healthy.

Heart Chambers
See what your heart looks like on the inside.

Heart Valves
Find out what makes the sound of your heartbeat.

Blood Flow Through Your Heart and Lungs
See the path blood takes on its way through your heart and lungs.

Your Heart's Electrical System
Learn how electricity keeps your heart beating.

Electrical Signals and Blood Flow
See how electricity and blood flow are related, and learn how doctors record the electrical activity in your heart.

Explore Blood Vessels

Intro to Blood Vessels
Learn about different kinds of blood vessels and about blood pressure.

Blood Vessels In Your Heart
Find out how your heart muscle gets its oxygen and nutrients.

Blood Vessels Outside Your Heart
Learn how your organs get their oxygen and nutrients.

Compare Conditions

Cardiovascular Disease:
Blood Vessel and Heart Problems

Compare common heart conditions—like heart attack, heart failure, and others—and see exactly how they affect the heart.

Show What You Know

Take our short, interactive heart quiz.