What is the heart?
The heart is a fist-sized organ that pumps blood throughout your body. It's the primary organ of your circulatory system.
Your heart contains four main sections (chambers) made of muscle and powered by electrical impulses. Your brain and nervous system direct your heart’s function.
What does a heart diagram look like?
The inside and outside of your heart contain components that direct blood flow:
Inside of the Heart
Outside of the Heart
What is the heart’s function?
Your heart’s main function is to move blood throughout your body. Your heart also:
- Controls the rhythm and speed of your heart rate.
- Maintains your blood pressure.
How does your heart work with other organs?
Your heart works with other body systems to control your heart rate and other body functions. The primary systems are:
- Nervous system: Your nervous system helps control your heart rate. It sends signals that tell your heart to beat slower during rest and faster during stress.
- Endocrine system: Your endocrine system sends out hormones. These hormones tell your blood vessels to constrict or relax, which affects your blood pressure. Hormones from your thyroid gland can also tell your heart to beat faster or slower.
Where is your heart located?
Your heart is located in the front of your chest. It sits slightly behind and to the left of your sternum (breastbone). Your ribcage protects your heart.
What side is your heart on?
Your heart is slightly on the left side of your body. It sits between your right and left lungs. The left lung is slightly smaller to make room for the heart in your left chest.
How big is your heart?
Everyone’s heart is a slightly different size. Generally, adult hearts are about the same size as two clenched fists, and children’s hearts are about the same size as one clenched fist.
How much does your heart weigh?
On average, an adult’s heart weighs about 10 ounces. Your heart may weigh a little more or a little less, depending on your body size and sex.
What are the parts of the heart’s anatomy?
The parts of your heart are like the parts of a house. Your heart has:
- Chambers (rooms).
- Valves (doors).
- Blood vessels (plumbing).
- Electrical conduction system (electricity).
Your heart walls are the muscles that contract (squeeze) and relax to send blood throughout your body. A layer of muscular tissue called the septum divides your heart walls into the left and right sides.
Your heart walls have three layers:
- Endocardium: Inner layer.
- Myocardium: Muscular middle layer.
- Epicardium: Protective outer layer.
The epicardium is one layer of your pericardium. The pericardium is a protective sac that covers your entire heart. It produces fluid to lubricate your heart and keep it from rubbing against other organs.
Your heart is divided into four chambers. You have two chambers on the top (atrium, plural atria) and two on the bottom (ventricles), one on each side of the heart.
- Right atrium: Two large veins deliver oxygen-poor blood to your right atrium. The superior vena cava carries blood from your upper body. The inferior vena cava brings blood from the lower body. Then the right atrium pumps the blood to your right ventricle.
- Right ventricle: The lower right chamber pumps the oxygen-poor blood to your lungs through the pulmonary artery. The lungs reload blood with oxygen.
- Left atrium: After the lungs fill blood with oxygen, the pulmonary veins carry the blood to the left atrium. This upper chamber pumps the blood to your left ventricle.
- Left ventricle: The left ventricle is slightly larger than the right. It pumps oxygen-rich blood to the rest of your body.
Your heart valves are like doors between your heart chambers. They open and close to allow blood to flow through.
The atrioventricular (AV) valves open between your upper and lower heart chambers. They include:
- Tricuspid valve: Door between your right atrium and right ventricle.
- Mitral valve: Door between your left atrium and left ventricle.
Semilunar (SL) valves open when blood flows out of your ventricles. They include:
- Aortic valve: Opens when blood flows out of your left ventricle to your aorta (artery that carries oxygen-rich blood to your body).
- Pulmonary valve: Opens when blood flows from your right ventricle to your pulmonary arteries (the only arteries that carry oxygen-poor blood to your lungs).
Your heart pumps blood through three types of blood vessels:
- Arteries carry oxygen-rich blood from your heart to your body’s tissues. The exception is your pulmonary arteries, which go to your lungs.
- Veins carry oxygen-poor blood back to your heart.
- Capillaries are small blood vessels where your body exchanges oxygen-rich and oxygen-poor blood.
Your heart receives nutrients through a network of coronary arteries. These arteries run along your heart’s surface. They serve the heart itself.
- Left coronary artery: Divides into two branches (the circumflex artery and the left anterior descending artery).
- Circumflex artery: Supplies blood to the left atrium and the side and back of the left ventricle.
- Left anterior descending artery (LAD): Supplies blood to the front and bottom of the left ventricle and the front of the septum.
- Right coronary artery (RCA): Supplies blood to the right atrium, right ventricle, bottom portion of the left ventricle and back of the septum.
Electrical conduction system
Your heart’s conduction system is like the electrical wiring of a house. It controls the rhythm and pace of your heartbeat. It includes:
- Sinoatrial (SA) node: Sends the signals that make your heart beat.
- Atrioventricular (AV) node: Carries electrical signals from your heart’s upper chambers to its lower ones.
Your heart also has a network of electrical bundles and fibers. This network includes:
- Left bundle branch: Sends electric impulses to your left ventricle.
- Right bundle branch: Sends electric impulses to your right ventricle.
- Bundle of His: Sends impulses from your AV node to the Purkinje fibers.
- Purkinje fibers: Make your heart ventricles contract and pump out blood.
Conditions and Disorders
What conditions and disorders affect the human heart?
Heart conditions are among the most common types of disorders affecting people. In the United States, heart disease is the leading cause of death for people of all genders and most ethnic and racial groups.
Common conditions that affect your heart include:
- Atrial fibrillation (Afib): Irregular electrical impulses in your atrium.
- Arrhythmia: A heartbeat that is too fast, too slow or beats with an irregular rhythm.
- Cardiomyopathy: Unusual thickening, enlargement or stiffening of your heart muscle.
- Congestive heart failure: When your heart is too stiff or too weak to properly pump blood throughout your body.
- Coronary artery disease: Plaque buildup that leads to narrow coronary arteries.
- Heart attack (myocardial infarction): A sudden coronary artery blockage that cuts off oxygen to part of your heart muscle.
- Pericarditis: Inflammation in your heart’s lining (pericardium).
How can I keep my heart healthy?
If you have a condition that affects your heart, follow your healthcare provider’s treatment plan. It’s important to take medications as prescribed.
You can also make lifestyle changes to keep your heart healthy. You may:
- Achieve and maintain a healthy weight for your sex and age.
- Drink alcohol in moderation.
- Eat a heart-healthy diet with plenty of fruits, vegetables and whole grains.
- Exercise moderately for at least 150 minutes per week.
- Limit your sodium intake.
- Manage your stress with healthy strategies like meditation or journaling.
- Quit smoking and/or using tobacco products and avoid secondhand smoke.
Frequently Asked Questions
What should I ask my doctor about my heart?
You may want to ask your healthcare provider:
- How does my family history affect my heart health?
- What can I do to lower my blood pressure?
- How do my cholesterol levels affect my heart?
- What are the symptoms of a heart attack?
- What foods should I eat to prevent heart disease?
A note from Cleveland Clinic
Your heart is the primary organ of your circulatory system. It pumps blood throughout your body, controls your heart rate and maintains blood pressure. Your heart is a bit like a house. It has walls, rooms, doors, plumbing and an electrical system. All the parts of your heart work together to keep blood flowing and send nutrients to your other organs. Conditions that affect your heart are some of the most common types of conditions. Ask your healthcare provider how you can improve your heart health.
The heart's primary function is to pump blood throughout the body. It supplies oxygen and nutrients to the tissues and removes carbon dioxide and waste from the blood.What is the anatomy and function of the heart? ›
The heart is a fist-sized organ that pumps blood throughout your body. It's the primary organ of your circulatory system. Your heart contains four main sections (chambers) made of muscle and powered by electrical impulses. Your brain and nervous system direct your heart's function.What are the 12 parts of heart? ›
- Left atrium and auricle. Left atrium. Left auricle.
- Right atrium and auricle. Right atrium. Right auricle.
- Interventricular septum and septal papillary muscles. Interventricular septum. ...
- Right ventricle and papillary muscles. Right ventricle. ...
- Left ventricle and papillary muscles. Left ventricle.
The right ventricle pumps the low-oxygen blood to the lungs to pick up a fresh supply of oxygen. The left atrium receives to high-oxygen blood from the lungs and pumps it to the left ventricle. The left ventricle pumps the high-oxygen blood to the rest of the body.What are the 3 main functions of the heart? ›
As the central part of the circulatory system, the heart is responsible for pumping blood, supplying oxygen and nutrients, and removing metabolic waste such as carbon dioxide from all the tissues in the body.What are the 4 main parts of the heart? ›
The heart is made up of four chambers. The upper two chambers are called atria (singular: atrium) and the lower two are known as ventricles (singular: ventricle). Muscular walls, called septa or septum, divide the heart into two sides.What are the 4 main arteries of the heart? ›
The right coronary artery, the left main coronary, the left anterior descending, and the left circumflex artery, are the four major coronary arteries. Blockage of these arteries is a common cause of angina, heart disease, heart attacks and heart failure.How many main functions does the heart have? ›
The four main functions of the heart are: Pumping oxygenated blood to other body parts. Pumping hormones and other vital substances to different parts of the body. Receiving deoxygenated blood and carrying metabolic waste products from the body and pumping it to the lungs for oxygenation.What is the basic functional unit of the heart? ›
The smallest functional unit of the heart at the micrometer scale is the sarcomere (typically spans 1.5 to 2 μm). Sarcomeres are aligned anisotropically in the cardiomyocytes (typical dimensions: length 110 μm, width 25 μm 18), which are assembled as continuous muscle sheets.What are the 17 segments of the heart? ›
|Left Anterior Descending (LAD)||1, 2, 7, 8, 13, 14, 17|
|Right Coronary Artery (RCA)||3, 4, 9, 10, 15|
|Left Circumflex (LCX)||5, 6, 11, 12, 16|
The human heart is a four-chambered muscular organ, shaped and sized roughly like a man's closed fist with two-thirds of the mass to the left of midline. The heart is enclosed in a pericardial sac that is lined with the parietal layers of a serous membrane.What are the 5 cardiac areas? ›
The 5 points of auscultation of the heart include the aortic, pulmonic, tricuspid, and mitral valve as well as an area called Erb's point, where S2 is best heard. The five points of auscultation of the heart center around the heart valves and allow the listener to hear detailed mechanics of each heart valve.What is the heart made of? ›
Your heart is made up of three layers of tissue: epicardium. myocardium. endocardium.What are the 3 layers of the heart called? ›
The wall of the heart separates into the following layers: epicardium, myocardium, and endocardium. These three layers of the heart are embryologically equivalent to the three layers of blood vessels: tunica adventitia, tunica media, and tunica intima, respectively.What is the most powerful part of the heart? ›
The left ventricle is the strongest of your heart's pumps. Its thicker muscles need to perform contractions powerful enough to force the blood to all parts of your body.What color is the heart without blood? ›
The heart will appear white if it has been drained of blood.What is the biggest artery? ›
Your heart pumps oxygen-rich blood into the biggest artery in your body — your aorta.Which artery causes most heart attacks? ›
Other causes include:
- Coronary artery spasm. ...
- Certain infections. ...
- Spontaneous coronary artery dissection (SCAD).
This condition is called atherosclerosis. The buildup is called plaque. Plaque can cause the arteries to narrow, blocking blood flow. The plaque can also burst, leading to a blood clot.Which heart artery is most important? ›
The most important artery is called the left anterior descending artery (LAD). It feeds blood to the whole front wall of the heart, which represents much more muscle than the area fed by either of the other two coronary arteries.
A typical heart has two upper and two lower chambers. The upper chambers, the right and left atria, receive incoming blood. The lower chambers, the more muscular right and left ventricles, pump blood out of the heart. The heart valves, which keep blood flowing in the right direction, are gates at the chamber openings.What are the 8 parts of heart? ›
The heart is made up of four chambers: two upper chambers known as the left atrium and right atrium and two lower chambers called the left and right ventricles. It is also made up of four valves: the tricuspid, pulmonary, mitral and aortic valves.How many heart types are there? ›
In humans, other mammals, and birds, the heart is divided into four chambers: upper left and right atria and lower left and right ventricles. Commonly the right atrium and ventricle are referred together as the right heart and their left counterparts as the left heart.What does LCx mean? ›
The Left Coronary Artery has two major branches; they are called the Left Anterior Descending (LAD) and the Left Circumflex (LCx) coronary arteries. The LAD supplies blood and oxygen to the anterior portion of the left ventricle. The LCx supplies blood and oxygen to the lateral portion of the left ventricle.Why is the human heart divided into two? ›
The right and left sides of the heart are separated by a muscular wall that prevents blood without oxygen from mixing with blood that has oxygen. The heart also has valves that separate the chambers and connect to major blood vessels.Is the heart a Muscle or an organ? ›
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.What exactly is the heart? ›
The heart is an organ about the size of your fist that pumps blood through your body. It is made up of multiple layers of tissue. Your heart is at the center of your circulatory system.Where exactly is the heart located? ›
The heart is located between the right and left lungs in the middle of your chest. The heart's function is to supply oxygen and blood to all parts of the body.What does an S4 heart sound mean? ›
The fourth heart sound, S4, also known as 'atrial gallop' results from the contraction of the atria pushing blood into a stiff or hypertrophic ventricle, indicating failure of the left ventricle. From: Biology of Cardiovascular and Metabolic Diseases, 2022.What type of muscle is the heart? ›
Overview. The 3 types of muscle tissue are cardiac, smooth, and skeletal. Cardiac muscle cells are located in the walls of the heart, appear striped (striated), and are under involuntary control.
|Part of||The heart wall|
|Latin||Textus muscularis striatus cardiacus|
Your heart has a special electrical system called the cardiac conduction system. This system controls the rate and rhythm of the heartbeat. With each heartbeat, an electrical signal travels from the top of the heart to the bottom. As the signal travels, it causes the heart to contract and pump blood.What part of the heart has 3 flaps? ›
Aortic valve: This valve has three leaflets. They open to let blood flow from your heart's left ventricle to the aorta. The aorta is the largest blood vessel in your body. It brings oxygenated blood from your heart to the rest of your body.What carries blood away from the heart? ›
Arteries. Blood vessels that carry oxygenated blood away from the heart to the body.What is the shape of a heart? ›
According to the Heart Institute, "The heart is shaped like an upside-down pear." As for its size... A normal, healthy heart is the size of an average clenched adult fist.What is the function of the heart quizlet? ›
The function of the heart is to contract and pump oxygenated blood to the body and deoxygenated blood to the lungs.What is the heart short answer? ›
The heart is an organ that beats continuously to act as a pump for the transport of blood, which carries other substances with it. The heart pumps the deoxygenated blood to the lungs for oxygenation and receives oxygenated blood from the lungs. It pumps the oxygenated blood to different parts of the body.What is the function of the heart Quizizz? ›
What is the main function of the heart ? The heart pumps blood and oxygen throughout the body.How big is the heart what is its function answer? ›
Your heart is a vital organ. It is a muscle that pumps blood to all parts of your body. The blood pumped by your heart provides your body with the oxygen and nutrients it needs to function. Your heart is about the size of a clenched fist, and weighs between 300 and 450 g.What are the four functions of the heart? ›
- Its significant role is to pump blood throughout the body.
- Enables transport of oxygen-rich blood to all components of the body.
- Helps regulate adequate blood pressure throughout the body.
- Transfers nutrients to cells, tissues, and all parts of the body.
The heart's primary function is to pump blood throughout the body. It supplies oxygen and nutrients to the tissues and removes carbon dioxide and waste from the blood.What is the heart quizlet? ›
The heart is a transport system pump that propels the blood through a system of vessels. It's role is to ensure the delivery of oxygenated blood to the cells, tissues and organs of the body and the return of deoxygenated blood to the lungs.How many functions does the heart have? ›
The four main functions of the heart are: Pumping oxygenated blood to other body parts. Pumping hormones and other vital substances to different parts of the body. Receiving deoxygenated blood and carrying metabolic waste products from the body and pumping it to the lungs for oxygenation.How many arteries are in the heart? ›
The 2 main coronary arteries are the left main and right coronary arteries.