Human heart is a very important part of a body.Wilhout heart no life is possible.Heart is a type of pump which distribute blood to various parts of the body.It is very important organ of a human body so it need a right care.We must known that what is right and what is wrong for your heart.If we able to known how heart work you will able to live a longer life in a peaceful way.

As we take a survey in America there is a thousand of people die due to the heart problem. This means that there is a death in every 56 second.Now a day a good thing is that death rate is decreasing as we compare it to the past but still there is death due to heart diseaes.Most of the people die even before they reach the hospital or to the doctor.

The Human Heart

Heart is a cone shaped and hollow part of the body situated in between the lungs  and just behind the sternum. According to a human body two third of the heart is situated to the left and one third is situated to the right of body as shown in a following figure. 

The size of the apex is 5 inches long and 4 inches wide and 3 inches from front to back.As we compare a female heart to a male heart there is a slight difference in weight female heart is about 9.2 ounces and male heart is around 10.5 ounces.When we compare the weight of the heart as compare to weight  of the body it is only 0.6 % of body weight. The heart comprises of three layers  such as below:---

1.Endocardium.

2.Myocardium.

3.pericardium.

The human heart is classified into four chambers are as follow:---

right atrium

right ventricle

left atrium

left ventricle

Every chamber in a heart has a one way valve and it function is to prevent flowing of blood from outside the heart. It open way of the chamber when contraction of valve take place. After the contraction this path is close it prevent the overflow of blood from outside the heart.

There are different type of valve these are as follow:-----

Tricuspid valve :--- This valve is called the exit of the Right Atrium.

The pulmonary valve :--- This valve is called the exit of the Right Ventricle.

Mitral valve :--- This valve is called the exit of the Left Atrium.

Aortic valve :---- This valve is called the exit of the Left Ventricle.

The blood is pumped out when there is contraction in the heart muscles. Human heart contract in two of the process. According to the first process there is a contraction in the right and left atrium this contraction take place at the same time and blood is pumped into Right and left Ventricle. In the second process the Ventricles contract at the same time and remove blood out of the heart. Now at last the heart muscles relaxes so that blood again fill to heart just before the next heartbeat. This is a regular process and this two process take place several times till the life possible.

Heart is comprises of the two side right and left each side have a separate function.The right side of a human heart play a important role it function is to collect a blood that contain oxygen and carbon dioxide and from the body and transfer it to the lungs and lungs collect all the oxygen and releases carbon dioxide. Now the left side of the heart collect a blood that contain a lots of oxygen from the lungs and then  transfer it to the different part of the body.In this way every cell get a good amount of oxygen and a person is able to perform their day to day activity.

Blood Flow 

The blood enter into the heart through a vein known as :---

1.Superior Vena Cava

2.Inferior Vena Cava     

The function of the Superior Vena Cava is to collect all blood from the upper parts of the body whereas Inferior Vena Cava collect blood from the lower parts of the body.All the collected blood is transfer into the Right Atrium As we see in the below figure.

 Now the blood transfer into the Right Ventricles through a Tricuspid valve from the Right Atrium by the process of contraction. The blood is transfer into the Pulmonary Artery through a Pulmonary valve from the Right Atrium by the process of contraction and then it into the lungs where it enrich with oxygen.

What is need of this process as we know that it collect blood from the body which is very poor in oxygen. To give a energy to the body it needs to rich with a oxygen. So the right side of the heart take blood and transfer it to the lungs and then blood is rich with oxygen and then it transfer it to the left side of the heart and after that it again returned it to the body to perform a various kind of activity.

Now the lungs transfer blood to the heart with the help of a Pulmonary veins and that blood is transfer into the Left Atrium .After the contraction of the Left Atrium blood is transfer into the Left Ventricles by the way of Mitral valve .The Left Ventricles is a very important chamber in the heart that transfer blood into the aorta through a aortic Valve. The Aorta is Consider as the main artery of the body. It Function is to receives all the blood that the heart has pumped out of the heart and then it distributes it to the rest of the body by this person is able to perform a lots of activity. The Left Ventricles pumped the blood to the body at a very high speed for that function it has a thick layer of muscles as we compare it to other part of the heart. Lets us know that how blood flow from body to lungs where it take oxygen and how it transfer it to the body just see in a quick reviews.

1):--- Blood move from body to lungs where it take oxygen:---

1. Blood flow from the body to the Superior Vena Cava and Inferior Vena cava.

2.Then it flow to the Right Atrium.

3.Now it flow to the Tricuspid Valve.

4.Now it flow it to the Right Ventricles passing through the Pulmonary valve it reach to the Pulmonary Artery

5.And at last it reach to the lungs where it takes oxygen and transfer it to the body.

2):--- Now blood flow from the lungs and transfer it to the body in a way:---

1.Blood flow from lungs to the Pulmonary Veins.

2.Now it reach to the Left Atrium.

3.It reach to the Left Ventriclespassing through Mitral valve.

4.It reach to the Aorta passing through the Aortic valve.

5.At last it reach to the body where it gives energy for performing various kind of activity.

The Body Electrical System.

Now we going to learn that what makes our heart to beat and in a regular way. It is really a amazing thing for us. 

In our body there is a special type of cell which function is to produce a electrical activity by their own. These special cell remove some of the charge and allow it to flow into the blood cell. By this process it  develop a electric impulse and this impulse spread over the heart and for this reason heart contract. The capacity of this cell is to produce more than one per second which help to generate a heart beat at a rate of 72 beats per minute.

In the Right Atrium there is a Sinoatrial Node which is also known as a natural pacemaker of heart.The heart collect electrical impulse from the Pacemaker with the help of a special fibres. 

First of all electrical impules  passes through the SA node and then it reaches to the right and left atria .With the passes of the electric  impules it makes to contract with each other. After contraction it reaches to the AV Node. Now it reaches to the Bundle of His.From there it is divided into the Right bundle branch and Left Bundle branch. From there it is spread to the right and left  Ventricles with the help of a purkinje Fibres. By this it contract to each other. There is a Pacemaker present in the Heart  which is also known as Electrical Tissue.SA Node is consider as the best Pacemaker because it generate a higher impulse rate.Suppose that if SA Node fail to perform a function of a pacemaker then other electrical part of Heart take place but in a slower rate as we compare to a SA Node.

The function of a Pacemaker is to create a electrical impulse which help to beat the heart.There is a another nerves that can effect the beating of heart rate.These are the type of nerves which is a part of a Autonomic nervous system.It has two parts are as follow:----

sympathetic nervous system – It function is to increase the Heart rate and power of contraction.

parasympathetic nervous system – It function is to Decrease the Heart rate and power of contraction.

Above all the activity produce a electric wave and we can measure this wave by using  an Electrocardiogram.The below figure clearly proof that in a better way:---

Each tracing has its own name such as given below:------

P Wave – It conside over the Atria and start contraction.

QRS Complex – It conside over the Ventricles and start contraction.

T Wave – It consides with the recovery phase of the Ventricles.

Blood Supply

We keep a habit of eating clean food in our diet it help to keep Coronary Arteries in a working condition and it prevent Heart attack.

Heart also require pure blood that contain oxygen and useful nutrients to work in a proper manner.Heart does not take oxygen and Nutrients from the blood itself. It take blood from the Coronary Arteries that is flow inside the muscles of Heart.

There are two type of Coronary Arteries. These are as follow:---

The Left main Coronary Arteries.

The Right Coronary Arteries.

The Left Main Coronary Arteries are further divided into two parts these are as follow:-----

Left Circumflex Artery.

Left Anterior Descending Branch.

There is a Vein inside the heart that contain the poor blood from the muscles of the Heart.Some of the major Vein in the Heart area as follow:----

great cardiac vein.

 small cardiac vein.

 middle cardiac vein.

 posterior vein of the left ventricle.

 and oblique vein of the left atrium.