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Blood Flow Through the Heart

Aparna Jadhav

The human heart is an important organ of our body, which pumps blood, and circulates it throughout the body. Read on to find out the path of blood flow through the body and heart.
Anatomically, the heart is a muscular organ, which is found in all animals having a circulatory system. This organ is responsible for the pumping of blood throughout the blood vessels in the body, through repetitive rhythmic contractions and expansions.
It is said that the human heart beats approximately 2.5 billion times during an average lifespan of 66 years. The average heart rate is 72 beats per hour, and it weighs 250 to 300 grams in females, and 300 to 350 grams in males. The structure of this organ is very typical, and it differs from other vertebrate hearts.

Structure of the Human Heart

► It is commonly an upside down, pear shaped hollow shell, which is divided into four chambers inside.
► These chambers are known as the left and right atria, and the left and right ventricles; from time to time, are filled with blood, and are emptied.

► The two atria situated to the left and right, form the curved top of the heart, and are located above the left and right ventricles.
► Similarly the ventricles meet each other at the bottom of the heart to give it a pointed base, which points towards the left side of the chest.

► Now, since the left ventricle contracts with the most force, the heartbeat is felt strongly at the left of the chest.
► The septum is a wall that separates the right and left sides of the heart, and is present in between the right atrium and ventricle, and the left atrium and ventricle.

► Both atria and the ventricles are connected to each other through a valve, and the mitral or the bicuspid valve connects the 2 atria and ventricles of the right and left side to each other.
For the process of blood flow, it is essential to know that there are three ways, by which the blood is pumped through the heart, and then moves into the lungs. This process takes place in the following manner:

Both Sides Work Together

Even though the right and the left side of the heart work together in pumping the oxygenated and de-oxygenated blood, they still have their individual functions.
Right side: There are two large veins, the inferior and the superior vena cava, which are present in the right side heart, and through which the blood enters. Through these veins, the oxygen poor blood from the body is emptied into the right atrium.
Left side: On the left side, the pulmonary vein empties the oxygen rich blood, which is brought from the lungs to the left atrium.

Atrial Contraction

After the oxygen poor and rich blood is emptied into the right and left atria respectively, the atrial contraction takes place, which also happens in the right and left sides of the heart.
Right side: The blood that has entered the right atrium, flows into your right ventricle through the open tricuspid valve, and when the ventricles are full, the valve shuts. This prevents the blood from flowing back into the atria while the ventricles contract.
Left side: Similarly, the blood from the left atrium flows into the left ventricle through the open mitral valve, and when the ventricles are full, this valve also shuts for the same reason.

Ventricular Contraction

Once the atria have done their job, and transferred both the oxygen poor and rich blood into the ventricles, the ventricular contraction begins.
Right side: Once the right ventricle has contracted, the blood leaves the heart through the pulmonic valve, and enters into the pulmonary artery and lungs. This is the de-oxygenated blood, which is purified in the lungs, and is pumped back into the heart.
Left side: Similarly, once the left ventricle has contracted, the blood from this one leaves the heart through the aortic valve, and enters the aorta and is carried into the body. This is the pure oxygenated blood, which is passed all over the body for further metabolism.
The described process happens almost every second of life. Once our blood stops flowing, we might get a heart attack. Other heart problems or even death might result due to the accumulation of blood in a certain organ.
There are many cardiovascular diseases that are caused due to the malfunctioning of the blood flow. Thus, the constant process of purification of blood and transporting it throughout our body is a very important job done by our cardiovascular system.