Heart | Structure, Function, Diagram, Anatomy, & Facts

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Jun. 7, 2023, 5:09 PM ET (AP)

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Top Questions

Where is the heart located in the human body?

In humans, the heart is situated between the two lungs and slightly to the left of center, behind the breastbone. It rests on the diaphragm, the muscular partition between the chest and the abdominal cavity.

What is the heart wall made up of?

The heart consists of several layers of a tough muscular wall, the myocardium. A thin layer of tissue, the pericardium, covers the outside, and another layer, the endocardium, lines the inside.

What causes the heart to beat?

The pumping of the heart, or the heartbeat, is caused by alternating contractions and relaxations of the myocardium. These contractions are stimulated by electrical impulses from a natural pacemaker, the sinoatrial, or S-A, node located in the muscle of the right atrium.

What are heart sounds?

The rhythmic noises accompanying the heartbeat are called heart sounds. The two distinct sounds are heard, a low, slightly prolonged “lub” (first sound) occurring at the beginning of ventricular contraction or systole and a sharper, higher-pitched “dup” (second sound), caused by the closure of aortic and pulmonary valves at the end of systole.

heart, organ that serves as a pump to circulate the blood. It may be a straight tube, as in spiders and annelid worms, or a somewhat more elaborate structure with one or more receiving chambers (atria) and a main pumping chamber (ventricle), as in mollusks. In fishes the heart is a folded tube, with three or four enlarged areas that correspond to the chambers in the mammalian heart. In animals with lungs—amphibians, reptiles, birds, and mammals—the heart shows various stages of evolution from a single to a double pump that circulates blood (1) to the lungs and (2) to the body as a whole.

In humans and other mammals and in birds, the heart is a four-chambered double pump that is the centre of the circulatory system. In humans it is situated between the two lungs and slightly to the left of centre, behind the breastbone; it rests on the diaphragm, the muscular partition between the chest and the abdominal cavity.

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Human Organs

The heart consists of several layers of a tough muscular wall, the myocardium. A thin layer of tissue, the pericardium, covers the outside, and another layer, the endocardium, lines the inside. The heart cavity is divided down the middle into a right and a left heart, which in turn are subdivided into two chambers. The upper chamber is called an atrium (or auricle), and the lower chamber is called a ventricle. The two atria act as receiving chambers for blood entering the heart; the more muscular ventricles pump the blood out of the heart.

Explore the human heart and how the cardiovascular system help circulate blood throughout the body

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The heart, although a single organ, can be considered as two pumps that propel blood through two different circuits. The right atrium receives venous blood from the head, chest, and arms via the large vein called the superior vena cava and receives blood from the abdomen, pelvic region, and legs via the inferior vena cava. Blood then passes through the tricuspid valve to the right ventricle, which propels it through the pulmonary artery to the lungs. In the lungs venous blood comes in contact with inhaled air, picks up oxygen, and loses carbon dioxide. Oxygenated blood is returned to the left atrium through the pulmonary veins. Valves in the heart allow blood to flow in one direction only and help maintain the pressure required to pump the blood.

The low-pressure circuit from the heart (right atrium and right ventricle), through the lungs, and back to the heart (left atrium) constitutes the pulmonary circulation. Passage of blood through the left atrium, bicuspid valve, left ventricle, aorta, tissues of the body, and back to the right atrium constitutes the systemic circulation. Blood pressure is greatest in the left ventricle and in the aorta and its arterial branches. Pressure is reduced in the capillaries (vessels of minute diameter) and is reduced further in the veins returning blood to the right atrium.

Listen to an exposed human heartbeat during open-heart surgery

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The pumping of the heart, or the heartbeat, is caused by alternating contractions and relaxations of the myocardium. These contractions are stimulated by electrical impulses from a natural pacemaker, the sinoatrial, or S-A, node located in the muscle of the right atrium. An impulse from the S-A node causes the two atria to contract, forcing blood into the ventricles. Contraction of the ventricles is controlled by impulses from the atrioventricular, or A-V, node located at the junction of the two atria. Following contraction, the ventricles relax, and pressure within them falls. Blood again flows into the atria, and an impulse from the S-A starts the cycle over again. This process is called the cardiac cycle. The period of relaxation is called diastole. The period of contraction is called systole. Diastole is the longer of the two phases so that the heart can rest between contractions. In general, the rate of heartbeat varies inversely with the size of the animal. In elephants it averages 25 beats per minute, in canaries about 1,000. In humans the rate diminishes progressively from birth (when it averages 130) to adolescence but increases slightly in old age; the average adult rate is 70 beats at rest. The rate increases temporarily during exercise, emotional excitement, and fever and decreases during sleep. Rhythmic pulsation felt on the chest, coinciding with heartbeat, is called the apex beat. It is caused by pressure exerted on the chest wall at the outset of systole by the rounded and hardened ventricular wall.

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The rhythmic noises accompanying heartbeat are called heart sounds. Normally, two distinct sounds are heard through the stethoscope: a low, slightly prolonged “lub” (first sound) occurring at the beginning of ventricular contraction, or systole, and produced by closure of the mitral and tricuspid valves, and a sharper, higher-pitched “dup” (second sound), caused by closure of aortic and pulmonary valves at the end of systole. Occasionally audible in normal hearts is a third soft, low-pitched sound coinciding with early diastole and thought to be produced by vibrations of the ventricular wall. A fourth sound, also occurring during diastole, is revealed by graphic methods but is usually inaudible in normal subjects; it is believed to be the result of atrial contraction and the impact of blood, expelled from the atria, against the ventricular wall.

Heart “murmurs” may be readily heard by a physician as soft swishing or hissing sounds that follow the normal sounds of heart action. Murmurs may indicate that blood is leaking through an imperfectly closed valve and may signal the presence of a serious heart problem. Coronary heart disease, in which an inadequate supply of oxygen-rich blood is delivered to the myocardium owing to the narrowing or blockage of a coronary artery by fatty plaques, is a leading cause of death worldwide.

The Editors of Encyclopaedia BritannicaThis article was most recently revised and updated by Adam Augustyn.

Coronary angiogram – Better Health Channel

Summary

Read the full fact sheet

• A coronary angiogram is a special procedure that takes dynamic x-ray pictures of your heart.  
• The purpose of this procedure is to see if the coronary arteries are narrowed or blocked and to look for abnormalities of heart muscle or heart valves.
• You may undergo various tests before the angiogram, including blood tests, an electrocardiogram, chest x-ray or cardiac CT.

A coronary angiogram is a special procedure that takes dynamic x-ray pictures of your heart. The purpose of this procedure is to see if your coronary arteries are narrowed or blocked and to look for abnormalities of your heart muscle or heart valves. Another term for coronary angiogram is cardiac catheterisation.

The test is done in a special laboratory called a cardiac catheterisation laboratory (cath lab), which is similar to an operating theatre.

A slender catheter (a thin, hollow plastic tube) is threaded through the largest artery in your body (the aorta) via the wrist or the groin artery until it reaches the coronary arteries of the heart. A special x-ray sensitive dye (contrast) is injected and dynamic x-rays are taken of the blood vessels as the contrast moves through them.

Problems diagnosed by coronary angiogram

Apart from diseased coronary arteries, an angiogram can also diagnose a range of heart problems including aneurysm (abnormal ballooning of the heart wall), heart arrhythmias (irregular heart beat) or birth defects, such as a hole in the heart.

Medical issues to consider before having an angiogram

Before the procedure, you need to discuss a range of issues with your doctor including:

• your medical history, including whether or not you have asthma, allergies or kidney disease
• if you have experienced allergic reactions to any drugs
• any current medications you are taking. You may need to discontinue certain medications before the test, such as medications that thin the blood
• fasting – you need to fast four to six hours prior to your test
• other tests – you may undergo various tests before the angiogram, including blood tests, an electrocardiogram and chest x-ray and cardiac CT (computed tomography).

Coronary angiogram procedure

Most diagnostic coronary angio procedures are done as day cases. That means that you are in and out of hospital within one day. Before the procedure, a nurse will take your medical history and you will change into a hospital gown. The nurse will prepare you for the procedure by putting in an IV cannula and shaving both sides of your groin and wrist if necessary.

Once in the cath lab, you will lie on a special table. A heart monitor will record your heart beat during the test. The skin on your wrist and both sides of your groin is cleaned with an antiseptic wash and you are covered with sterile drapes.

The doctor injects a small amount of local anaesthetic around the access site (wrist or groin) to numb the area then inserts a small catheter through the skin into the blood vessel. The doctor watches the progress of the catheter via dynamic x-rays transmitted to a television monitor.

You can’t feel the catheter going through the heart because there are not enough nerves in the blood vessels. Once the catheter is in place, a small amount of contrast (x-ray sensitive dye) is injected through it. Further dynamic x-rays are taken as the contrast goes through the blood vessels. You may feel a warm flush or tingling as the contrast is injected. The angiogram lasts for around 40 minutes.

Immediately after the coronary angiogram

After the angiogram, you can expect the following:

• Your blood pressure, pulse, breathing and wound site are regularly checked and recorded.
• You may be given intravenous fluids for a short time, although you will be encouraged to eat and drink as soon as you feel able.
• You may be allowed to sit up after four hours.
• You may be discharged to go home up to six hours post (after) recovery.
• If you are not already on a special diet, you will be encouraged to adopt a cholesterol-lowering diet.
• Initial results are given to you by the cardiologist who performed the procedure. You may have to make follow up appointment with a cardiologist to further discuss your treatment.

Complications of a coronary angiogram

Some of the possible complications of a coronary angiogram include:

• allergic reaction to the contrast dye, including hives and itchy skin
• bleeding from the wound
• heart arrhythmia
• heart attack
• stroke.

Taking care of yourself at home after a coronary angiogram

Be guided by your doctor, but general suggestions include:

• Try to rest as much as you can.
• Avoid standing for more than a few minutes at a time.
• Avoid heavy lifting for at least a week after the procedure.
• See your doctor if you suspect infection. Symptoms include redness, heat, swelling or discharge from the wound site.
• Drink plenty of fluids eight hours after the procedure (unless told otherwise by your cardiologist) to help flush the contrast from your body.

Long-term outlook after a coronary angiogram

You will need to make another appointment with your doctor to discuss the results of your angiogram. Treatment depends on the diagnosis.

Narrowed coronary arteries may possibly be treated during the angiogram by a technique known as angioplasty. A special catheter is threaded through the blood vessels and into the coronary arteries to remove the blockage.

Another surgical option for severely narrowed coronary arteries is a bypass operation. This involves transplanting veins and arteries from other parts of your body to your heart.

Other heart tests

Currently, the angiogram is the most accurate diagnostic test for a range of heart problems, including coronary heart disease. Other tests that can help in diagnosis but can’t provide conclusive results include:

• exercise stress test
• computed tomography (CT) scan
• magnetic resonance imaging (MRI) scan
• echocardiogram (special ultrasound of the heart).

Where to get help

• Your GP (doctor)
• Cardiologist

• Coronary angiogram – a guide for patientsExternal Link, Monash Heart, Monash Health, Clayton South, Victoria

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May 16, 2023, 17:13

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Communication on the Internet is a real art. Corresponding with a girl can be a powerful tool for dating and building relationships. How to achieve this, experts told GQ magazine.

What to write to a girl when meeting?

According to the experts of Lychee magazine, when meeting a girl on the Internet or social networks, it is important to show sincere interest. Carefully study the page of the chosen one. This will help write her a catchy message.

Hello. I see you love concerts. And we have the same taste in music.

Could you tell me the way to your heart or at least to a phone number?

Noticed something interesting. Judging by the photo, we often visit the same cafes at the same time. It’s strange that we haven’t noticed each other until now, isn’t it?

I see we have a lot of mutual friends. How do you know Ivan Ivanov?

I lost the bet and now I have to meet the most beautiful girl on the internet. Will you give me a chance?

I came across your photo from Cyprus. I have long wanted to visit this island. Did you like it there? Will you share your impressions?

According to your profile, I know your name and what you look like. Let me verify the veracity of this information and get to know you better?

I thought online dating was a waste of time. But then I came across your page.

Tell me what a guy should write to interest you?

Hello. I am an employee of the employment service and I really want to keep you busy with something interesting in the very near future. Do not mind?

When sending a first message to a girl you don’t know, don’t forget to say hello. But don’t stop with a short “Hi!” or “Good afternoon!”. Appreciate the interlocutor’s time and explain why you decided to disturb her.

Phrases for communicating with a girl on the Internet: NUR.KZ

Phrases for keeping up a conversation with a girl

After meeting online or dating in real life, it is important not to miss the chance and not push the girl away. To do this, it is necessary to build a dialogue correctly, to interest the interlocutor. The phrases below will help in this:

You know, many people tend to embellish their lives. Do you often do this?

What masculine quality can push you headlong into the pool?

As a child, I dreamed of seeing all the seven wonders of the world. Are you interested in antiquities?

Are you ready to radically change your life if such an opportunity appears tomorrow?

I wake up easily at dawn. Are you an owl or a lark?

Do you believe in the existence of kindred spirits?

What do you listen to more often in a relationship – the voice of your heart or reason?

Do you believe that accidents are not accidental?

You have an amazing figure. Do you spend a lot of time on sports?

Do you often go to photo shoots? I think photographers should line up to take pictures of you.

Are you ready to commit some kind of madness, succumbing to the signs of fate?

Write questions and phrases that push the interlocutor to lengthy reflections. Show interest in the girl and her opinion, but do not turn the dialogue into an interrogation with passion.

Phrases for chatting with a girl: NUR.KZ

Phrases for flirting with a girl

When talking with a girl on the Internet, flirt. Use slightly provocative and non-banal compliments or phrases with a hint for this purpose. Examples of the most successful messages are given below.

Such a tigress definitely needs a worthy tiger nearby!

I wonder if your inner world is as beautiful as your outside?

How is the mood of the one who stole my heart?

Today it is somehow irrelevant to ask about the son-in-law, but I really want to.

Do you have a strong thread to make our acquaintance?

I thought a lot about you today, and it’s still only morning!

You deprived me of sleep and rest, how will you correct the situation?

If you’re tired of the whistle that follows you, just say it. Ready to drive away annoying fans from you day and night.

The best thing that happens to me in the morning is you and coffee.

I think I’m drunk. More precisely, intoxicated by your beauty.

Did you have time to drink coffee in the morning? If not, I’m ready to bring it to you at work.

When flirting with a pen pal, remember to be polite. Make sure that your communication does not cause discomfort in the interlocutor and a desire to stop communication.

Phrases for communication with a girl: NUR.KZ

Pleasant words and compliments for a girl

According to the editors of GQ magazine, an unsuccessfully formulated compliment can offend the interlocutor, and not please her. What to write a pleasant girl in your own words? Philologist and writer Svetlana Smyshlyak advises to be attentive both to the appearance and to the interests of the girl, her achievements, and her inner world.

This outfit perfectly highlights the color of your eyes.

You know, your face could grace the cover of Cosmopolitan.

Do you want to see incredible beauty? Then go to the mirror!

On a 10-point beauty scale, you are 1000 points.

A million compliments on your feet.

Your smile is the best thing I have ever seen in my life.

You shine like a polar star!

Mother Nature did her best when she created you.

Your shining eyes make you believe in a brighter future.

Makeup usually enhances a woman’s beauty, but you look amazing even without it.

According to research by Naomi K. Grant, Ph.D., Ph.D., and her colleagues, compliments encourage people to reciprocate. Therefore, having heard pleasant words addressed to her, the girl on a subconscious level will want to continue the conversation.

Phrases for communication with a girl: NUR.KZ

Phrases that will cheer up a girl

What to write to a girl in the morning? A message sent in the morning can contain wishes for a good day, jokes, and even declarations of love.

You are as beautiful as the first rays of the morning sun.

Good morning! Thinking of you. I hope you slept well today.

Good morning! Wake up, I miss you.

Good morning! Although if you were there, it would be kinder.

Good morning! I would like to be the sun to gently caress your face every morning when you wake up.

Good morning! I hope you are smiling now.

I want to wish good morning to the queen of my heart!

You can express admiration for your interlocutor and please her not only in the morning, but also at other times of the day. What to write to a girl to make her smile? Use one of the phrases below.

If someone says that miracles don’t happen, I’ll show them your picture.

You should start decorating interiors. As soon as you enter the room, it becomes very beautiful.

No matter how my day went, your smile makes the difference.

If you decided to conquer Hollywood, all popular actresses would be out of work.

You are as mysterious and bewitching as a solar eclipse.

I am ready to build a palace and try on a shoe for you, just to make you believe in a fairy tale.

Have you already left to decorate this world or are you taking a day off today?

Don’t give a girl banal compliments hoping to make her smile. Be sincere and be creative.

Phrases for communication with a girl: NUR.KZ

Communication with the opposite sex requires attention, resourcefulness and skill from men. It is not enough to meet a beautiful girl, it is also important to maintain a conversation competently.