# data[].attributes.attachment_link.readable_text
Matthew Busse

Matthew Busse has pursued professional health and science writing since 2007, writing for national publications including "Science Magazine," "New Scientist" and "The Scientist." Busse holds a doctorate in molecular biology from the University of California-San Diego.

The cardiovascular system, also known as the circulatory system, includes the heart, arteries, veins, capillaries and blood. The heart functions as the pump that moves blood through the body. The arterial circulation delivers blood from the heart to the body, and the venous circulation carries it back to the heart. Capillaries are tiny blood vessels at the interface of the arterial and venous circulation where exchange of substances between the blood and body tissues occurs. The cardiovascular system serves several major functions that are necessary for life.

Video of the Day

Supplying oxygen to the body is the most essential function of the cardiovascular system. Although all cells require oxygen, brain cells are the most sensitive and begin to die in as little as 3 minutes if deprived of oxygen. During inhalation, air enters the lungs and oxygen is absorbed through the air sacs into the bloodstream. This oxygen-rich blood is pumped through the heart into the arterial circulation. In the capillaries, oxygen diffuses out of the blood and into the cells of the body's organs and tissues. At the same time, carbon dioxide -- a waste product produced by cells -- is absorbed into the blood and transported to the lungs through the venous circulation. When this oxygen-poor blood reaches the lungs, carbon dioxide diffuses through the air sacs and is then exhaled. This cycle occurs with every breath.

Delivering nutrients to the body is another critical function of the cardiovascular system. After food is digested in the stomach and intestines, its component nutrients are absorbed into the bloodstream. These nutrients include sugars, fats, vitamins, minerals and protein building blocks called amino acids. Each of these nutrients is vital to healthy body function. For example, the sugar glucose is the body's primary fuel to generate energy, and amino acids enable the body to manufacture new cells. Like oxygen, nutrients diffuse from the bloodstream into body cells via the capillaries. In addition to carbon dioxide, the circulatory system picks up metabolic waste products and toxins and transports them to the liver, kidneys and lungs for eventual elimination from the body.

The circulatory system serves as the highway for disease-fighting cells and proteins, and messengers of the immune system. Immune system cells called white blood cells patrol the body in search of invading germs. If an infection occurs, these cells send chemical alarm signals that travel through the bloodstream, which subsequently transports infection-fighting cells to the site of the infection. The circulatory system also carries chemical messengers that attract cells to heal tissues that have been damaged due to injury or disease.

Hormones are chemical messengers produced by endocrine glands that affect distant organs. The cardiovascular system serves as the transportation connection between the endocrine glands and the organs or tissues they control via hormones. For example, hormones produced in the pituitary gland in the brain control other endocrine glands -- such as the thyroid, ovaries and testes -- as well as directing childhood growth. Similarly, the blood-sugar-lowering hormone insulin produced in the pancreas affects the uptake and use of blood sugar throughout the body. And thyroid hormones affect the metabolic rate of virtually every body organ and tissue, thanks to their body-wide delivery via the circulatory system.

Body temperature regulation is an often overlooked but important function of the cardiovascular system. Optimal function of the human body occurs within a relatively narrow temperature range, which is tightly regulated. If body temperature begins to rise, blood vessels close to the body surface dilate, increasing in size. This allows the body to rid itself excess heat through the skin. Conversely, if body temperature drops, surface blood vessels constrict to conserve body heat. The cardiovascular system works in concert with the body's sweating mechanism as the primary regulators of body temperature.

Reviewed by: Tina M. St. John, M.D.

Anatomy and Physiology: Understanding the Human Body; Robert K. Clark

Cardiovascular Physiology Concepts; Richard Klabunde

Virginia State Department of Health: Care of the Circulatory System

Physiology and Pathophysiology of Temperature Regulation; Clark M. Blatteis

# data[].attributes.attachment_link.title
5 Major Functions of the Cardiovascular System

# data[].attributes.attachment_link.description
The cardiovascular system, also known as the circulatory system, includes the heart, arteries, veins, capillaries and blood. The heart functions as the pump that moves blood through the body. The arterial circulation delivers blood from the heart to the body, and the venous circulation carries it back to the heart.

# data[].attributes.attachment_link.readable_text
An Introduction to the Cardiovascular System

The cardiovascular system can be thought of as the transport system of the body. This system has three main components: the heart, the blood vessel and the blood itself. The heart is the system's pump and the blood vessels are like the delivery routes. Blood can be thought of as a fluid which contains the oxygen and nutrients the body needs and carries the wastes which need to be removed. The following information describes the structure and function of the heart and the cardiovascular system as a whole.

Structure and Function of the Heart
Function and Location of the Heart
The heart's job is to pump blood around the body. The heart is located in between the two lungs. It lies left of the middle of the chest.
Structure of the Heart
The heart is a muscle about the size of a fist, and is roughly cone-shaped. It is about 12cm long, 9cm across the broadest point and about 6cm thick. The pericardium is a fibrous covering which wraps around the whole heart. It holds the heart in place but allows it to move as it beats. The wall of the heart itself is made up of a special type of muscle called cardiac muscle.
Chambers of the Heart
The heart has two sides, the right side and the left side. The heart has four chambers. The left and right side each have two chambers, a top chamber and a bottom chamber. The two top chambers are known as the left and right atria (singular: atrium). The atria receive blood from different sources. The left atrium receives blood from the lungs and the right atrium receives blood from the rest of the body. The bottom two chambers are known as the left and right ventricles. The ventricles pump blood out to different parts of the body. The right ventricle pumps blood to the lungs while the left ventricle pumps out blood to the rest of the body. The ventricles have much thicker walls than the atria which allows them to perform more work by pumping out blood to the whole body.
Blood Vessels
Blood Vessel are tubes which carry blood. Veins are blood vessels which carry blood from the body back to the heart. Arteries are blood vessels which carry blood from the heart to the body. There are also microscopic blood vessels which connect arteries and veins together called capillaries. There are a few main blood vessels which connect to different chambers of the heart. The aorta is the largest artery in our body. The left ventricle pumps blood into the aorta which then carries it to the rest of the body through smaller arteries. The pulmonary trunk is the large artery which the right ventricle pumps into. It splits into pulmonary arteries which take the blood to the lungs. The pulmonary veins take blood from the lungs to the left atrium. All the other veins in our body drain into the inferior vena cava (IVC) or the superior vena cava (SVC). These two large veins then take the blood from the rest of the body into the right atrium.
Valves
Valves are fibrous flaps of tissue found between the heart chambers and in the blood vessels. They are rather like gates which prevent blood from flowing in the wrong direction. They are found in a number of places. Valves between the atria and ventricles are known as the right and left atrioventricular valves, otherwise known as the tricuspid and mitral valves respectively. Valves between the ventricles and the great arteries are known as the semilunar valves. The aortic valve is found at the base of the aorta, while the pulmonary valve is found the base of the pulmonary trunk. There are also many valves found in veins throughout the body. However, there are no valves found in any of the other arteries besides the aorta and pulmonary trunk.
What is the Cardiovascular System?
The cardiovascular system refers to the heart, blood vessels and the blood. Blood contains oxygen and other nutrients which your body needs to survive. The body takes these essential nutrients from the blood. At the same time, the body dumps waste products like carbon dioxide, back into the blood, so they can be removed. The main function of the cardiovascular system is therefore to maintain blood flow to all parts of the body, to allow it to survive. Veins deliver used blood from the body back to the heart. Blood in the veins is low in oxygen (as it has been taken out by the body) and high in carbon dioxide (as the body has unloaded it back into the blood). All the veins drain into the superior and inferior vena cava which then drain into the right atrium. The right atrium pumps blood into the right ventricle. Then the right ventricle pumps blood to the pulmonary trunk, through the pulmonary arteries and into the lungs. In the lungs the blood picks up oxygen that we breathe in and gets rid of carbon dioxide, which we breathe out. The blood is becomes rich in oxygen which the body can use. From the lungs, blood drains into the left atrium and is then pumped into the left ventricle. The left ventricle then pumps this oxygen-rich blood out into the aorta which then distributes it to the rest of the body through other arteries. The main arteries which branch off the aorta and take blood to specific parts of the body are:

The body is then able to use the oxygen in the blood to carry out its normal functions. This blood will again return back to the heart through the veins and the cycle continues.

What is the Cardiac Cycle?

The cardiac cycle is the sequence of events that occurs in one complete beat of the heart. The pumping phase of the cycle, also known as systole, occurs when heart muscle contracts. The filling phase, which is known as diastole, occurs when heart muscle relaxes. At the beginning of the cardiac cycle, both atria and ventricles are in diastole. During this time, all the chambers of the heart are relaxed and receive blood. The atrioventricular valves are open. Atrial systole follows this phase. During atrial systole, the left and right atria contract at the same time and push blood into the left and right ventricles, respectively. The next phase is ventricular systole. During ventricular systole, the left and right ventricles contract at the same time and pump blood into the aorta and pulmonary trunk, respectively. In ventricular systole, the atria are relaxed and receive blood. The atrioventricular valves close immediately after ventricular systole begins to stop blood going back into the atria. However, the semilunar valves are open during this phase to allow the blood to flow into the aorta and pulmonary trunk. Following this phase,Â the ventricles relax that is ventricular diastole occurs. The semilunar valves close to stop the blood from flowing back into the ventricles from the aorta and pulmonary trunk. The atria and ventricles once again are in diastole together and the cycle begins again.

Components of the Heartbeat

The adult heart beats around 70 to 80 times a minute at rest. When you listen to your heart with a stethoscope you can hear your heart beat. The sound is usually described as "lubb-dupp". The "lubb" also known as the first heart sound, is caused by the closure of the atrioventricular valves. The "dupp" sound is due to the closure of the semilunar valves when the ventricles relax (at the beginning of ventricular diastole). Abnormal heart sounds are known as murmurs. Murmurs may indicate a problem with the heart valves, but many types of murmur are no cause for concern. (For more information see: (see Valvular Heart Disease)

The Electrocardiogram

The heart has an inbuilt rhythm of contraction and relaxation. A small group of heart muscle cells called the pacemaker help achieve this. The pacemaker generates an electrical impulse which spreads over the atria, making them contract. This impulse then spreads to the ventricles, causing them to contract. The electrical changes that spread through the heart can be detected at the surface of the body by an instrument called the electrocardiograph. Electrodes are placed in a number of positions over the chest and the electrical changes are recorded on moving graph paper as an electrocardiogram (ECG).

Effects of Aging on the Heart in Men and Women

As a part of the normal aging process a number of changes occur to the cardiovascular system.

Our heart rate slows down because the time between heartbeats increases as we age. This is one of the main reasons why the heart is unable to pump out more blood during exercise when we become old.

The amount of blood the heart pumps each minute can change as we age. It decreases slightly in older women. However, it does not change in healthy older men who have no heart disease. The reason for the difference between the sexes is not fully understood.

As we age, our blood pressure falls much more on standing from the sitting position compared to when we are younger. This phenomenon is known as postural hypotension. This explains why elderly people are more likely to feel dizzy or to fall when they stand up quickly from a resting position.

References

1. Beers, M. (editor-in-chief) "Aging and the Cardiovascular System"[online], The Merck Manual of Geriatrics. Merck & Co. Inc. 2006. Available at URL: http://www.merck.com/mrkshared/mmg/search.jsp (last accessed: 30/6/06)

2. Guyton, A and Hall, J. (editors) Textbook of medical physiology. Philadelphia, W. B. Saunders, 2000.

3. Johnson, L. (editor) Essential medical physiology. Philadelphia, Lippincott-Raven, 1998.

4. Saladin, K. Anatomy & physiology: the unity of form and function. Boston, McGraw-Hill, 2001.

5. Talley, N and O'Connor, S. Clinical examination: a guide to physical diagnosis. Sydney, MacLennan & Petty, 2001.

# data[].attributes.attachment_link.title
Anatomy of the human heart and cardiovascular system | myVMC

# data[].attributes.attachment_link.description
The cardiovascular system can be thought of as the transport system of the body. This system has three main components: the heart, the blood vessel and the blood itself. The heart is the system's pump and the blood vessels are like the delivery routes.

# data[].attributes.attachment_link.readable_text
By David Terfera, Shereen Jegtvig

The cardiovascular system is part of the larger circulatory system, which circulates fluids throughout the body. The circulatory system includes both the cardiovascular system and the lymphatic system. The cardiovascular system moves blood throughout the body, and the lymphatic system moves lymph, which is a clear fluid that's similar to the plasma in blood.

Blood contains nutrients from the foods you eat and oxygen from the air you breathe. It also contains hormones and cells that fight infection. The blood also transports waste products to various places that then promptly remove the waste from the body.

The parts of the cardiovascular system include the heart, which is the organ that pumps the blood, and a network of blood vessels:

Arteries: The blood vessels that take blood away from the heart

Veins: Blood vessels that return blood to the heart

Capillaries: Very small vessels that lie between the arteries and veins

The portal vein and its tributaries carry blood from parts of the digestive system to the liver before reaching the heart.

The heart is a muscular pump with four chambers inside: the right and left atria and the right and left ventricles. Those four chambers allow the heart to pump blood through the following two circulatory pathways:

Here's the pathway taken by the blood while it's in systemic circulation, delivering oxygen-rich blood throughout the body:

1. The left ventricle of the heart receives oxygenated blood from the left atrium.

2. Blood is ejected from the left ventricle into the aorta, a large artery.

The ascending aorta sends blood to the upper thorax, upper extremities, neck, and head.

The descending aorta sends blood to the lower thorax, the abdomen, the pelvis, and the lower extremities.

3. The blood leaves the ascending and descending parts of the aorta and enters a network of systemic arteries that run to all places of the body.

4. Blood passes from the smallest arteries (called arterioles) into the capillary beds. In the capillary beds, blood exchanges oxygen, nutrients, and waste products with the tissues.

5. The oxygen-poor blood leaves the capillary beds via small veins (called venules) and drains into a network of systemic veins that eventually lead to the venae cavae (either of the two large veins leading into the heart).

The superior vena cava receives blood from the upper thorax, head, neck, and upper extremities.

The inferior vena cava receives blood from the lower thorax, the abdomen, the pelvis, and the lower extremities.

6. The venae cavae empty the oxygen-poor blood into the right atrium of the heart.

After systemic circulation, the blood in the right atrium is depleted of oxygen, so it needs to go to the lungs to exchange carbon dioxide for oxygen. The pathway from the heart to the lungs and back to the heart is called pulmonary circulation, and it takes the following path:

1. The right ventricle receives the oxygen-depleted blood from the right atrium.

2. The blood leaves the right ventricle and enters the pulmonary trunk, which splits into two pulmonary arteries.

3. The pulmonary arteries lead to the lungs, where exchange of gases takes place. Carbon dioxide is removed from the blood, and oxygen enters the blood.

4. Blood leaves the lungs via the pulmonary veins.

The pulmonary veins carry freshly oxygenated blood to the heart while the systemic veins carry oxygen-poor blood to the heart.

5. The oxygenated blood enters the left atrium of the heart.

The blood in the left atrium moves into the left ventricle and enters the systemic circulation.

A number of problems can be classified as cardiovascular disease. The problems can occur after a person has developed atherosclerosis, also known as "hardening of the arteries," which results in decreased blood flow because the blood vessels are plugged. It occurs when fat, cholesterol, and calcium build up within the walls of the arteries. These build-ups, called plaques, can block the arteries and reduce the flexibility of the arterial walls. Atherosclerosis is common in older people, especially in those who have high blood pressure, are diabetic, have high cholesterol, eat too much saturated fat, drink too much alcohol, smoke, don't get enough exercise, and are overweight or obese. Blood clots can also form in the diseased vessels and stop blood flow completely, depriving tissues of oxygen.

Heart attacks (myocardial infarcts) occur when blood flow to some part of the heart is blocked, causing damage to part of the heart. Arrhythmia is a problem with the heart rhythm; the heart may beat too slow, too fast, or irregularly.

Cardiovascular disease can affect the brain as well. Ischemic strokes happen when a blood vessel in the brain is blocked. Hemorrhagic strokes occur when a blood vessel in the brain breaks open. Either type of stroke can result in damage to a part of the brain.

# data[].attributes.attachment_link.title
What Is the Cardiovascular System? - dummies

# data[].attributes.attachment_link.description
The cardiovascular system is part of the larger circulatory system, which circulates fluids throughout the body. The circulatory system includes both the cardiovascular system and the lymphatic system. The cardiovascular system moves blood throughout the body, and the lymphatic system moves lymph, which is a clear fluid that's similar to the plasma in blood.

# data[].attributes.attachment_link.readable_text
It's a muscle, about the size of your fist, in the middle of your chest tilted slightly to the left.

What is the function of the human heart?

Each day, your heart beats around 100,000 times. This continuously pumps about five litres (eight pints) of blood around your body through a network of blood vessels called your circulatory system. This blood delivers oxygen and nutrients to all parts of your body to help your organs and muscles work properly. Your blood also carries away unwanted carbon dioxide and waste products.

What is the structure of the human heart?

Your heart has a left side and a right side, they are separated by a thin muscular wall called the Septum. Both sides of your heart have an upper chamber and a lower chamber.

the upper chambers are called the left atrium and the right atrium (or the atria)

the lower chambers are called the left ventricle and the right ventricle.

The right side of your heart receives the de-oxygenated blood that has just travelled round your body. It pumps the blood to your lungs to collect a fresh supply of oxygen. The left side of your heart pumps the re-oxygenated blood round your body again.

Your heart muscle is made up of three layers of tissue:

Pericardium - a thin, outer lining that protects and surrounds your heart.

Myocardium - a thick, muscular middle layer that contracts and relaxes to pump blood around of your heart.

Endocardium - a thin, inner layer that makes up the lining of the four chambers and the valves in your heart.

What does the heart's electrical system do?

Your heart's electrical system tells your heart when to contract and when to relax to keep your blood pumping regularly. The instructions to contract and relax are carried by electrical signals.

The electrical signals are sent from the sinus node which is known as your heart's natural pacemaker. Usually, the sinus node will send the electrical signals at a steady pace, but the pace can change depending on your emotions and if you are active or resting - this is your heart rate.

How does blood flow around the heart and the body?

Your heart is linked to the rest of the circulatory system with blood vessels called arteries and veins.

your arteries deliver oxygen-rich blood from the heart to other areas of your body

your veins return the de-oxygenated blood from your organs back to your heart

your arteries and veins are connected by even smaller blood vessels called capillaries.

Your blood flows around your heart and the rest of your body in one direction, like a one-way traffic system. Your heart valves control the direction of your blood flow, they act like doors that open and close with every heartbeat. There are four valves in your heart, they are:

the tricuspid valve and the pulmonary valve on the right side of the heart

the mitral valve and the aortic valve on the left side of your heart.

Like the rest of your body, your heart needs to be supplied with oxygen-rich blood to work properly too. The coronary arteries are the arteries responsible for supplying the heart with oxygenated blood. The coronary arteries are spread across the outside of the heart to deliver the blood.

How do your heart and lungs add oxygen to your blood?

Your blood flows through your heart and your lungs to become re-oxygenated before being pumped to the rest of your body. Oxygen is added to your blood in four main steps, they are:

The right atrium receives the low-oxygen blood that has just travelled round the body. The right atrium pumps the blood to the right 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 heart and circulatory diseases?

Sometimes the heart and circulatory system don't work like they should, this can cause heart and circulatory diseases (also called cardiovascular diseases). We fund research into these conditions and their risk factors, including:

What causes your heart and circulatory system to go wrong?

Problems with your heart and circulatory system, including heart attack or a stroke, are usually caused by a gradual build-up of fatty material (called atheroma) in the arteries around the heart and in the arteries that supply blood to your brain.

The fatty material lines the walls of heart's coronary arteries making the space for blood to flow narrower. When the arteries become narrowed and the blood flow is restricted, the arteries can't deliver enough blood to the heart and the brain, which can cause heart and circulatory diseases.

What puts me at risk of heart and circulatory disease?

Many heart and circulatory diseases share the same risk factors including:

Heart and circulatory diseases can be worrying but the good news is that there are lots of things you can do to reduce your risk of developing heart and circulatory diseases now.

Check your heart age

You can trust our health information

We've followed an eight-step process to make sure this content is reliable, accurate and trustworthy. Learn how we make our health information reliable and easy to understand.
Page last reviewed: August 2021
Next review due: August 2024
Support our life saving research

We're funding vital research to help prevent and treat people living with heart and circulatory diseases. But more needs to be done.
DONATE
Your support funds crucial research so that we can beat these conditions and save lives.

# data[].attributes.attachment_link.description
Find out how a healthy heart works and its role pumping blood around your body. Watch our short animated guide to your heart.

# data[].attributes.attachment_link.title
Westlife - When You're Looking Like That (Official Video)

# data[].attributes.attachment_link.readable_text
Matthew Busse

Matthew Busse has pursued professional health and science writing since 2007, writing for national publications including "Science Magazine," "New Scientist" and "The Scientist." Busse holds a doctorate in molecular biology from the University of California-San Diego.

The cardiovascular system, also known as the circulatory system, includes the heart, arteries, veins, capillaries and blood. The heart functions as the pump that moves blood through the body. The arterial circulation delivers blood from the heart to the body, and the venous circulation carries it back to the heart. Capillaries are tiny blood vessels at the interface of the arterial and venous circulation where exchange of substances between the blood and body tissues occurs. The cardiovascular system serves several major functions that are necessary for life.

Video of the Day

Supplying oxygen to the body is the most essential function of the cardiovascular system. Although all cells require oxygen, brain cells are the most sensitive and begin to die in as little as 3 minutes if deprived of oxygen. During inhalation, air enters the lungs and oxygen is absorbed through the air sacs into the bloodstream. This oxygen-rich blood is pumped through the heart into the arterial circulation. In the capillaries, oxygen diffuses out of the blood and into the cells of the body's organs and tissues. At the same time, carbon dioxide -- a waste product produced by cells -- is absorbed into the blood and transported to the lungs through the venous circulation. When this oxygen-poor blood reaches the lungs, carbon dioxide diffuses through the air sacs and is then exhaled. This cycle occurs with every breath.

Delivering nutrients to the body is another critical function of the cardiovascular system. After food is digested in the stomach and intestines, its component nutrients are absorbed into the bloodstream. These nutrients include sugars, fats, vitamins, minerals and protein building blocks called amino acids. Each of these nutrients is vital to healthy body function. For example, the sugar glucose is the body's primary fuel to generate energy, and amino acids enable the body to manufacture new cells. Like oxygen, nutrients diffuse from the bloodstream into body cells via the capillaries. In addition to carbon dioxide, the circulatory system picks up metabolic waste products and toxins and transports them to the liver, kidneys and lungs for eventual elimination from the body.

The circulatory system serves as the highway for disease-fighting cells and proteins, and messengers of the immune system. Immune system cells called white blood cells patrol the body in search of invading germs. If an infection occurs, these cells send chemical alarm signals that travel through the bloodstream, which subsequently transports infection-fighting cells to the site of the infection. The circulatory system also carries chemical messengers that attract cells to heal tissues that have been damaged due to injury or disease.

Hormones are chemical messengers produced by endocrine glands that affect distant organs. The cardiovascular system serves as the transportation connection between the endocrine glands and the organs or tissues they control via hormones. For example, hormones produced in the pituitary gland in the brain control other endocrine glands -- such as the thyroid, ovaries and testes -- as well as directing childhood growth. Similarly, the blood-sugar-lowering hormone insulin produced in the pancreas affects the uptake and use of blood sugar throughout the body. And thyroid hormones affect the metabolic rate of virtually every body organ and tissue, thanks to their body-wide delivery via the circulatory system.

Body temperature regulation is an often overlooked but important function of the cardiovascular system. Optimal function of the human body occurs within a relatively narrow temperature range, which is tightly regulated. If body temperature begins to rise, blood vessels close to the body surface dilate, increasing in size. This allows the body to rid itself excess heat through the skin. Conversely, if body temperature drops, surface blood vessels constrict to conserve body heat. The cardiovascular system works in concert with the body's sweating mechanism as the primary regulators of body temperature.

Reviewed by: Tina M. St. John, M.D.

Anatomy and Physiology: Understanding the Human Body; Robert K. Clark

Cardiovascular Physiology Concepts; Richard Klabunde

Virginia State Department of Health: Care of the Circulatory System

Physiology and Pathophysiology of Temperature Regulation; Clark M. Blatteis

# data[].attributes.attachment_link.title
5 Major Functions of the Cardiovascular System

# data[].attributes.attachment_link.description
The cardiovascular system, also known as the circulatory system, includes the heart, arteries, veins, capillaries and blood. The heart functions as the pump that moves blood through the body. The arterial circulation delivers blood from the heart to the body, and the venous circulation carries it back to the heart.

# data[].attributes.body
https://www.bhf.org.uk/informationsupport/how-a-healthy-heart-works

# data[].attributes.attachment_link.readable_text
It's a muscle, about the size of your fist, in the middle of your chest tilted slightly to the left.

What is the function of the human heart?

Each day, your heart beats around 100,000 times. This continuously pumps about five litres (eight pints) of blood around your body through a network of blood vessels called your circulatory system. This blood delivers oxygen and nutrients to all parts of your body to help your organs and muscles work properly. Your blood also carries away unwanted carbon dioxide and waste products.

What is the structure of the human heart?

Your heart has a left side and a right side, they are separated by a thin muscular wall called the Septum. Both sides of your heart have an upper chamber and a lower chamber.

the upper chambers are called the left atrium and the right atrium (or the atria)

the lower chambers are called the left ventricle and the right ventricle.

The right side of your heart receives the de-oxygenated blood that has just travelled round your body. It pumps the blood to your lungs to collect a fresh supply of oxygen. The left side of your heart pumps the re-oxygenated blood round your body again.

Your heart muscle is made up of three layers of tissue:

Pericardium - a thin, outer lining that protects and surrounds your heart.

Myocardium - a thick, muscular middle layer that contracts and relaxes to pump blood around of your heart.

Endocardium - a thin, inner layer that makes up the lining of the four chambers and the valves in your heart.

What does the heart's electrical system do?

Your heart's electrical system tells your heart when to contract and when to relax to keep your blood pumping regularly. The instructions to contract and relax are carried by electrical signals.

The electrical signals are sent from the sinus node which is known as your heart's natural pacemaker. Usually, the sinus node will send the electrical signals at a steady pace, but the pace can change depending on your emotions and if you are active or resting - this is your heart rate.

How does blood flow around the heart and the body?

Your heart is linked to the rest of the circulatory system with blood vessels called arteries and veins.

your arteries deliver oxygen-rich blood from the heart to other areas of your body

your veins return the de-oxygenated blood from your organs back to your heart

your arteries and veins are connected by even smaller blood vessels called capillaries.

Your blood flows around your heart and the rest of your body in one direction, like a one-way traffic system. Your heart valves control the direction of your blood flow, they act like doors that open and close with every heartbeat. There are four valves in your heart, they are:

the tricuspid valve and the pulmonary valve on the right side of the heart

the mitral valve and the aortic valve on the left side of your heart.

Like the rest of your body, your heart needs to be supplied with oxygen-rich blood to work properly too. The coronary arteries are the arteries responsible for supplying the heart with oxygenated blood. The coronary arteries are spread across the outside of the heart to deliver the blood.

How do your heart and lungs add oxygen to your blood?

Your blood flows through your heart and your lungs to become re-oxygenated before being pumped to the rest of your body. Oxygen is added to your blood in four main steps, they are:

The right atrium receives the low-oxygen blood that has just travelled round the body. The right atrium pumps the blood to the right 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 heart and circulatory diseases?

Sometimes the heart and circulatory system don't work like they should, this can cause heart and circulatory diseases (also called cardiovascular diseases). We fund research into these conditions and their risk factors, including:

What causes your heart and circulatory system to go wrong?

Problems with your heart and circulatory system, including heart attack or a stroke, are usually caused by a gradual build-up of fatty material (called atheroma) in the arteries around the heart and in the arteries that supply blood to your brain.

The fatty material lines the walls of heart's coronary arteries making the space for blood to flow narrower. When the arteries become narrowed and the blood flow is restricted, the arteries can't deliver enough blood to the heart and the brain, which can cause heart and circulatory diseases.

What puts me at risk of heart and circulatory disease?

Many heart and circulatory diseases share the same risk factors including:

Heart and circulatory diseases can be worrying but the good news is that there are lots of things you can do to reduce your risk of developing heart and circulatory diseases now.

Check your heart age

You can trust our health information

We've followed an eight-step process to make sure this content is reliable, accurate and trustworthy. Learn how we make our health information reliable and easy to understand.
Page last reviewed: August 2021
Next review due: August 2024
Support our life saving research

We're funding vital research to help prevent and treat people living with heart and circulatory diseases. But more needs to be done.
DONATE
Your support funds crucial research so that we can beat these conditions and save lives.

# data[].attributes.attachment_link.description
Find out how a healthy heart works and its role pumping blood around your body. Watch our short animated guide to your heart.

# data[].attributes.attachment_link.description
Knowing the functions of the cardiovascular system and the parts of the body that are part of it is critical in understanding the physiology of the human body.

# data[].attributes.body
https://www.cliffsnotes.com/study-guides/anatomy-and-physiology/the-cardiovascular-system/functions-of-the-cardiovascular-system