What is the name of the path blood takes from the heart to the lungs and then back to the heart?

The heart is an organ, about the size of a fist. It is made of muscle and pumps blood through the body. Blood is carried through the body in blood vessels, or tubes, called arteries and veins. The process of moving blood through the body is called circulation. Together, the heart and vessels make up the cardiovascular system.

Structure of the Heart

The heart has four chambers (two atria and two ventricles). There is a wall (septum) between the two atria and another wall between the two ventricles. Arteries and veins go into and out of the heart. Arteries carry blood away from the heart and veins carry blood to the heart. The flow of blood through the vessels and chambers of the heart is controlled by valves.

Blood Flow Through the Heart

(Abbreviations refer to labels in the illustration)

The heart pumps blood to all parts of the body. Blood provides oxygen and nutrients to the body and removes carbon dioxide and wastes. As blood travels through the body, oxygen is used up, and the blood becomes oxygen poor.

1. Oxygen-poor blood returns from the body to the heart through the superior vena cava (SVC) and inferior vena cava (IVC), the two main veins that bring blood back to the heart.
2. The oxygen-poor blood enters the right atrium (RA), or the right upper chamber of the heart.
3. From there, the blood flows through the tricuspid valve (TV) into the right ventricle (RV), or the right lower chamber of the heart.
4. The right ventricle (RV) pumps oxygen-poor blood through the pulmonary valve (PV) into the main pulmonary artery (MPA).
5. From there, the blood flows through the right and left pulmonary arteries into the lungs.
6. In the lungs, oxygen is put into the blood and carbon dioxide is taken out of the blood during the process of breathing. After the blood gets oxygen in the lungs, it is called oxygen-rich blood.
7. Oxygen-rich blood flows from the lungs back into the left atrium (LA), or the left upper chamber of the heart, through four pulmonary veins.
8. Oxygen-rich blood then flows through the mitral valve (MV) into the left ventricle (LV), or the left lower chamber.
9. The left ventricle (LV) pumps the oxygen-rich blood through the aortic valve (AoV) into the aorta (Ao), the main artery that takes oxygen-rich blood out to the rest of the body.

Updated by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

The heart is a complex organ. It uses four chambers, four valves, and many blood vessels to provide blood to the body. Blood flow itself is equally complex. It's a cycle that moves blood through the heart and to the lungs to get oxygen. It's then delivered throughout the body and brought back to the heart to restart the process.

The key function of the cardiovascular system is to consume, transport, and use oxygen whether you're moving or at rest. When blood flow is disrupted, there are serious health effects.

This article takes apart that complex process step by step. It also explains how blood flow can be disrupted.

The heart has two upper chambers—the left and right atriums—and two larger lower chambers—the left and right ventricles. A series of valves act like doorways to control blood flow in and out of these chambers.

The cardiac conduction system sends out electric impulses to make the heart muscle contract and relax. Those pulses set the rate and rhythm of your heartbeat.

Here are the steps of blood flow through the heart and lungs:

1. The blood first enters the right atrium.
2. The blood then flows through the tricuspid valve into the right ventricle.
3. When the heart beats, the ventricle pushes blood through the pulmonic valve into the pulmonary artery.
4. The pulmonary artery carries blood to the lungs where it “picks up” oxygen.
5. It then leaves the lungs to return to the heart through the pulmonary vein.
6. The blood enters the left atrium.
7. It drops through the mitral valve into the left ventricle.
8. The left ventricle then pumps blood through the aortic valve and into the aorta. The aorta is the artery that feeds the rest of the body through a system of blood vessels.
9. Blood returns to the heart from the body via two large blood vessels called the superior vena cava and the inferior vena cava. This blood carries little oxygen, as it is returning from the body where oxygen was used.
10. The vena cavas pump blood into the right atrium and the cycle begins all over again.

Arteries generally transport oxygen-rich blood. The pulmonary artery is unique. It is the only artery in the body that carries oxygen-poor blood.

Without valves, the ventricles of the heart couldn’t build up any force or pressure. It would be like pumping up a flat tire with a huge hole in it. No matter how much effort you put into pumping, the tire would never inflate.

In the case of the heart, blood would come into the chamber and just slosh through it. It would exit the valve at the bottom or upward in the wrong direction each time the ventricle tried to pump blood.

All four of the heart valves open and close at just the right times to keep the blood flowing through the heart in the right direction. Part of the sound of your heartbeat is valves closing.

The four chambers and valves of the heart work together to pump blood through the body using a network of blood vessels. Blood enters the two chambers on the right side of the heart. From there, it's carried to the lungs to gather oxygen. Oxygen-rich blood travels from the lungs into the left side of the heart. The heart pumps it into blood vessels that deliver it to the rest of the body.

A healthy heart normally beats anywhere from 60 to 70 times per minute when you're at rest. This rate can be higher or lower depending on your health and physical fitness. Athletes generally have a lower resting heart rate, for example.

Your heart rate rises when you move. That's because your muscles use oxygen while they work. The heart works harder to bring oxygenated blood where it is needed.

If you have an irregular heartbeat or cardiac symptoms like chest pain and shortness of breath, seek medical help immediately.

Disrupted or irregular heartbeats can affect blood flow through the heart. This can happen in many ways:

• Electrical pulses are impacted, causing an arrhythmia, or irregular heartbeat. Atrial fibrillation is a common form of this.
• Conduction disorders, or heart blocks, affect the cardiac conduction system. That's what regulates how electrical impulses move through the heart. The type of block—an atrioventricular (AV) block or bundle branch block—depends on where it is in the conduction system.
• Damaged or diseased valves can stop working well or leak blood in the wrong direction.
• A blocked blood vessel can disrupt blood flow gradually or suddenly. One example is a heart attack.

Lots of factors can influence blood flow. Movement, emotion, health, and fitness can affect your heart rate. Problems in your heart's electrical system can lead to irregular heartbeats. And blocks in your blood vessels or valve damage can disrupt healthy blood flow.

Blood flow is a cycle that involves your lungs, heart chambers, valves, and blood vessels. Electrical pulses make your heart muscles squeeze and release. That action pushes blood through the two chambers on the right side of your heart and out to the lungs where it gathers oxygen.

A vein then carries that oxygen-rich blood into the left side of the heart. The two chambers on the left thrust the blood into arteries that carry blood and oxygen to the whole body.

When any part of that complex system breaks down, your body suffers from the lack of oxygen. Arrhythmia, valve disorders, and blockages in your heart or blood vessels can cause serious health problems. They may come on gradually or suddenly.

Healthy blood flow is critical to overall health. Physical activity is one of the best ways to make sure your heart and lungs can function well over time.

If you have health issues, partner with your healthcare provider to determine the best way to keep your heart rate and rhythm—and your blood flow—healthy. It's one of the most important things you can do for a long life.

Frequently Asked Questions

• In what direction does blood flow through the heart?

  Blood flows through the heart in two directions at the same time. De-oxygenated blood enters the right side of the heart and is pumped towards the lungs to pick up oxygen. Then that oxygen-rich blood re-enters the heart on the left side and is pumped out to the cells of the body.

• What affects your heart rate?

  Exercise and movement force your heart to beat faster and raise your heart rate. Many factors can also affect your resting heart rate. These include:

  • Medication
  • Your level of physical fitness
  • Air temperature and humidity
  • Body position (standing, sitting, lying down)
  • Emotions (anxiety, stress)
  • Body mass

• Does exercise improve blood flow?

  Yes, exercise does improve blood flow. Exercise strengthens your heart muscle so it works more efficiently and supports blood flow. Exercise also helps you maintain a healthy weight. It reduces your risk of high cholesterol and high blood sugar, and improves blood vessel function. These factors help your blood circulate effectively.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

1. National Heart, Lung, and Blood Institute. Conduction Disorders.

2. Centers for Disease Control and Prevention. How the Heart Works.

3. National Heart, Lung, and Blood Institute. How the Heart Works.

4. American Heart Association. All About Heart Rate (Pulse).

5. Pinckard K, Baskin KK, Stanford KI. Effects of exercise to improve cardiovascular health. Front Cardiovasc Med. 2019;6:69. doi:10.3389/fcvm.2019.00069

• The Texas Heart Institute at St. Luke’s Episcopal Hospital. Heart Anatomy.

• YourHeartValve.com/Edwards Lifesciences. Basic Anatomy and Function of the Heart.