Anatomy of the Human Heart

About the heart:


The heart is the hardest working muscle in the human body. Located almost in the center of the chest, the adult human heart is about the size of two fists held side-by-side.

At an average rate of 80 times a minute, the heart beats about 115,000 times in one day or 42 million times in a year. During an average lifetime, the human heart will beat more than 3 billion times - pumping an amount of blood that equals about 1 million barrels. Even when a person is at rest, the heart continuously works hard.


How the heart works:


The cardiovascular system, composed of the heart and blood vessels, is responsible for circulating blood throughout your body to supply the tissues with oxygen and nutrients.


* The atria receive blood coming back to the heart.
* The ventricles pump the blood out of the heart.

Blood vessels, which compose a network of arteries and veins that carry blood throughout the body.

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

Four valves to prevent backward flow of blood.

* Each valve is designed to allow the forward flow of blood and prevent backward flow.

An electrical system of the heart that stimulates contraction of the heart muscle.






The human heart consists of four chambers as seen in the picture above. They are the right atrium, left atrium, left ventricle and right ventricle. The blood enters the heart from the superior and inferior vena cava into the right atrium. Then it goes to the right ventricle and is them pumped to the lungs via the pulmonary artery. Once purified it comes back via the pulmonary veins into the left atrium. It then fills the left ventricle below as it flows down through the mitral valve. The blood is now ready to flow back to the entire body. It does so, by entering the aorta under a pressure of about 120 mmHg (16KPa) systolic pressure as the left ventricle contracts, along with other chambers of heart.




Anatomy of the Human Heart



Blood is kept moving along its circular route by the pumping action of the heart. The heart consists of four chambers. The upper two chambers are the right and left atria. The right and left atria are thin-walled sacs, which receive blood from the body and the lungs, respectively. In both atria the upper half of their inside wall is smooth and forms the sinuses of the great veins that empty into it. The lower half of the inside surfaces of the atria is very rough.

The lower two chambers of the heart are the right and left ventricles. The ventricles have thick walls made up of cardiac muscle. Cardiac muscle is also present in the walls of the atria. This specialized type of muscle tissue is found only in the heart; its fibers branch in such a way that when they all contract, they squeeze the heart chamber and force blood out of it. The inner surfaces of both ventricles are covered with ridges called trabeculae. Irregular muscle bundles called papillary muscles give rise to chords which anchor the heart valves. Both the trabeculae and the papillary muscles make the inside walls of the ventricles very rough.

In humans, the chambers of the atria are joined to their adjacent ventricles by valves. The tricuspid valve lies between the right atrium and right ventricle and the bicuspid valve lies between the left atrium and left ventricle. There are also valves between the ventricular chambers and the great arteries which they feed. The pulmonary valve lies between the right ventricle and the pulmonary artery. The aortic valve lies between the left ventricle and the aorta. The valves prevent blood from being forced back into the chamber from which it was expelled, and thus keep the blood flowing in one direction.

The right atrium and ventricle receive oxygen-poor blood from the body and send it to the lungs; they are therefore considered the pulmonary side of the heart. The left atrium and ventricle receive oxygenated blood from the lungs and pump it back into the body; they are therefore considered the systemic side of the heart.

The pacemaker of the heart (SA node) is located in the upper right atrium near the opening of the vena cava. The pacemaker sets the normal rhythmic beat of the heart by coordinating the contractions of the heart chambers. The pacemaker first sends a signal along specialized cardiac muscle fibers in the walls of both atria to make them contract simultaneously. The signals then converge on another bundle of specialized cardiac muscle fibers, the atrioventricular node (AV node) located in the wall separating the two ventricles. The AV node sends the signal on to the walls of the ventricles to make them contract simultaneously.







human heart diagram valves






Jamnagar (Gujarat), Dec.27: A 22-year-old man in Gujarat’s Jamanagar District has been living with an unusual human anatomy since his birth. His heart lies slightly on the right side of his chest instead of left side as it is in the normal case.

Residing in Mithapur, Dilip Sadiya never knew why the palpitation of the heart used to come from the right side of his body until he learnt at a hospital recently.

"I have never fallen ill all these years. Just that some days back, I was seriously ill, and had to be admitted to hospital. That’s when doctors told me that my heart is on right side of my body. I was actually very surprised, since I had no clue about it since my birth," said Dilip Sadiya.

He is presently pursing Bachelor of Arts degree and claims to have been hale and hearty.

According to physiologists, it’s called Dextrocardia, an instance of the heart being situated on the right side of the body.

In such a case, the heart is 'flipped over' so that the structures that are normally on the right side of the chest are on the left, and vice versa. Yet the arteries and veins are connected in the internal network of circulation of blood. Doctors state that this occurs due to an abnormality in the development of heart during pregnancy.

Doctors believe that this sort of anatomy is found in one among 130,000 persons, though it doesn't have any significant affect on health.

"I examined Mr. Dilip on December 20. He is suffering from Dextrocardia. It is called Situs Inversus. It is one of the congenital anomalies. It is rare. But patient is having no complain and he can live a simple life," said Dr. Ray Mangia.

Dilip's parents view this rare placement of heart as God's unique creation bestowed upon their son which makes him stand apart. (ANI)





















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Human heart with coronary arteries



















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drawing of the health based human heart




Drawing of the coronary arterial circulation in the human heart. The normal human hears does not typically elicit collateralization; each area of myocardium is usually supplied by a single coronary artery. Ao = aorta; LAD = left anterior descending artery; LCx = left circumflex artery; PA = pulmonary artery; RCA = right coronary artery.























































Biological diagram of the heart



























Anatomical picture of the human heart.
























3D-image anaglyph human heart




















Human Heart