Blood rich in oxygen leaves the heart from the

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How the heart works
What is the role of blood flow through the heart?
What is the circulatory system?
Where does blood flow through the heart?
What is the order of blood flow through the heart, step by step?
What signals control your heartbeat?
How much blood does your heart pump?
What conditions or disorders affect your heart’s blood flow?
How can I improve my heart health?
Where does blood leave the heart?
What supplies oxygen

The heart is the hardest working muscle in the human body. Located almost in the center of the chest, a healthy adult heart is the size of a clenched adult fist. By age 70, the human heart will beat more than 2.5 billion times. The heart is always working. It pumps about 2,000 gallons of blood daily.

A child's heart works just as hard as an adult's heart. In fact, at rest, a baby's heart may beat up to 130 to 150 times a minute. An adult's heart often beats between 60 and 100 times a minute, at rest. The rate at which the heart pumps gradually slows down from birth to teen years.

The cardiovascular system is made up of the heart and blood vessels. It circulates blood throughout the body. A healthy cardiovascular system is vital to supplying the body with oxygen and nutrients.

How the heart works

The heart is a large, muscular organ that pumps blood filled with oxygen and nutrients through the blood vessels to the body tissues. It's made up of:

4 chambers. The 2 upper chambers are the atria. They receive and collect blood. The 2 lower chambers are the ventricles. They pump blood to other parts of your body. Here is the process:
- The right atrium receives blood from the body. This blood is low in oxygen. This is the blood from the veins.
- The right ventricle pumps the blood from the right atrium into the lungs to pick up oxygen and remove carbon dioxide.
- The left atrium receives blood from the lungs. This blood is rich in oxygen.
- The left ventricle pumps the blood from the left atrium out to the body, supplying all organs with oxygen-rich blood.
4 valves. The 4 valves are the aortic, pulmonary, mitral, and tricuspid valves. They let blood flow forward and prevent the backward flow.
Blood vessels. These bring blood to the lungs, where oxygen enters the bloodstream, and then to the body:
- The inferior and superior vena cava bring oxygen-poor blood from the body into the right atrium.
- The pulmonary artery carries oxygen-poor blood from the right ventricle into the lungs, where oxygen enters the bloodstream.
- The pulmonary veins bring oxygen-rich blood to the left atrium.
- The aorta carries oxygen-rich blood to the body from the left ventricle.
An electrical system that stimulates contraction of the heart muscle.

A network of arteries and veins also carry blood throughout the body:

Arteries transport blood from the heart to the body tissues.
Veins carry blood back to the heart.

Medical Reviewers:

Louise Cunningham RN BSN
Steven Kang MD

What is the role of blood flow through the heart?

Your heart is a powerful muscle, about the size of your fist. Every second, it pumps nutrient- and oxygen-rich blood to your body. With each heartbeat, your heart sends blood through your circulatory system.

Blood is crucial to remain alive. Blood carries oxygen and nutrients from your heart to other tissues throughout your body. It also carries waste products such as carbon dioxide away from your tissues.

What is the circulatory system?

Your circulatory system is a network of blood vessels. Blood vessels are small tubes that carry blood all over your body. Blood flows through three types of blood vessels:

Arteries carry oxygen-rich blood away from your heart.
Capillaries are tiny, thin blood vessels that connect veins and arteries.
Veins carry oxygen-poor blood from your body’s tissues back to your heart.

Where does blood flow through the heart?

Your heart itself is made of muscle nourished by blood vessels. Your heart has four chambers. The chambers are like rooms in the “house” of your heart. If you look at a diagram of a heart, these chambers divide into upper and lower chambers and left and right chambers.

Atria are your two upper heart chambers. You have a left atrium and a right atrium.
Ventricles are your two lower heart chambers. You have a left ventricle and a right ventricle.

Between the top and bottom chambers, you have heart valves. Heart valves open and close to allow for proper blood flow. Your valves ensure that blood flows only in one direction. These valves are:

Aortic valve connects your left ventricle and aorta (large artery that carries blood throughout your body).
Mitral valve connects your left atrium and left ventricle.
Pulmonary valve connects your right ventricle and pulmonary arteries (arteries that carry blood to your lungs).
Tricuspid valve connects your right atrium and right ventricle.

What is the order of blood flow through the heart, step by step?

The right and left sides of your heart work together to ensure blood flows throughout your whole body. Blood flows through your heart through a series of steps. These steps take place in the space of one heartbeat — just a second or two.

On the right side

Oxygen-poor blood from all over your body enters your right atrium through two large veins, your inferior vena cava and superior vena cava.
Your tricuspid valve opens to let blood travel from your right atrium to your right ventricle.
When your right ventricle is full it squeezes, which closes your tricuspid valve and opens your pulmonary valve.
Blood flows through your pulmonary artery to your lungs, where it gets oxygen.

On the left side

Oxygen-rich blood travels from your lungs to your left atrium through large veins called pulmonary veins.
Your mitral valve opens to send blood from your left atrium to your left ventricle.
When your left ventricle is full it squeezes, which closes your mitral valve and opens your aortic valve.
Your heart sends blood through your aortic valve to your aorta, where it flows to the rest of your body.

Blood flows through your heart from the right side to the left side and then back to the rest of your body.

What signals control your heartbeat?

Your heart contracts (beats) when it receives an electrical impulse from your sinoatrial (SA) node. This signal is called heart conduction. The SA node is your body’s “natural pacemaker,” setting your heart’s rhythm.

Heart conduction continues as the electrical signal moves to the atrioventricular (AV) node in your right atria. The signal then travels down the His-Purkinje system (a bundle of special fibers) and spreads to the rest of your heart.

How fast or slow your heart beats varies throughout the day. Your nervous system sends electrical signals and your endocrine system sends hormones that control your heart rate. These signals help your heart adapt to your body’s changing needs. For example, your heartbeat quickens when you run and slows when you sleep.

How much blood does your heart pump?

Your heart pumps about 2,000 gallons of blood each day. That’s enough to fill an 8-by-10-foot swimming pool!

It beats around 100,000 times daily. In an average life span of almost 79 years, your heart beats nearly 2.9 billion times.

What conditions or disorders affect your heart’s blood flow?

Some conditions can affect the pathway of blood flow in your heart. Some of these conditions include:

Arrhythmia: An irregular heartbeat, including atrial fibrillation and ventricular fibrillation.
Congestive heart failure: Damage or weakness in your heart muscle, making it harder for your heart to pump blood to the rest of your body.
Coronary artery disease: Hardening and narrowing of the arteries that carry blood to your heart muscle as a result of plaque buildup.
Heart attack (myocardial infarction): A sudden blockage in your coronary artery that cuts off oxygen to part of your heart muscle.
Heart valve disease: Heart valves that don’t work properly, including leaky heart valve and valve stenosis (narrowing).
Structural congenital heart defects: Problems with your heart structure that are present at birth, including bicuspid aortic valve disease.
Sudden cardiac arrest: Sudden loss of heart function because of a malfunction in your heart’s electrical system.

How can I improve my heart health?

You can take some steps to live a healthier lifestyle and improve your cardiovascular health. You may:

Achieve and maintain a weight that’s healthy for you.
Eat a heart-healthy diet full of fruits, vegetables and whole grains.
Exercise aerobically for around 150 minutes weekly.
Limit alcohol intake.
Manage stress with healthy coping techniques such as talk therapy or meditation.
Quit smoking.

A note from Cleveland Clinic

Every day, blood pumps throughout your heart and the rest of your body. The process of blood flowing through your heart is crucial for staying alive and healthy. When blood enters your heart, it is low in oxygen. Your heart sends the blood to your lungs, where it receives oxygen. Then, your heart pumps the oxygen- and nutrient-rich blood to the tissues and organs throughout your body.

Where does blood leave the heart?

The left ventricle generates the high pressure needed to pump the blood to your whole body through your blood vessels. When blood leaves the heart to go to the rest of the body, it travels through a large artery called the aorta.

What supplies oxygen

The aorta (the main blood supplier to the body) branches off into two main coronary blood vessels (also called arteries). These coronary arteries branch off into smaller arteries, which supply oxygen-rich blood to the entire heart muscle.