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Systemic Circulation

Systemic circulation, a part of circulatory system, consists of oxygenated blood flow from the heart to the body and deoxygenated blood flow from all the parts of the body to the heart.
Niharika Arya
Have you ever wondered why you have so many blood vessels in your body, how oxygen reaches each organ or how your heart helps in the functioning of your body? Yes, answer for all these questions can be explained by systemic circulation.
This circulation is related to the blood flow in the body and is a part of the circulatory system or the cardiovascular system. It is a very important process which helps our body to function properly. Following paragraphs will help you to understand its functions and its importance in sustaining life.

What is a Systemic Circulation?

Systemic blood circulation is a part of cardiovascular system or circulatory system. Circulatory system is divided in two parts: systemic circulation and pulmonary circulation.
In the former case, the purified blood from the heart is collected with the help of arteries and is supplied to different parts of the body. Then the impure blood from different parts of the body is taken to the heart with the help of veins. Then comes the role of pulmonary circulation which consists of purification of blood which is done in the lungs.
The heart provides the blood to the lungs where the carbon dioxide is removed from the blood cells and is replaced with oxygen. Then this oxygenated blood is transferred to the heart for further process.

Systemic Circulation Pathway

This circulation pathway includes arteries, arterioles, capillaries, veins, venules, etc. All these circulatory system organs participate in this process and are assigned with a particular work. Let's find out how oxygenated blood reaches different parts of our body and how deoxygenated blood is taken back to the heart for further purification.

Oxygenated Blood

The process starts when oxygenated blood is sent to the human heart from the lungs. The blood comes to the left atrium and then heart pumps out oxygenated blood to the left ventricle. From the left ventricle blood is pumped to the major artery known as aorta.
Aorta further divides into two main arteries. One artery goes up to the shoulder and head and the other goes down to the legs, stomach and other lower parts of the body. The artery going up divides into subclavian artery which goes to the shoulder and carotid artery which supplies blood to the head and the neck region.
The artery going downwards divides itself into hepatic artery which goes to the liver, renal artery which goes to the kidney, mesenteric artery which supplies blood to the stomach and intestine and finally the iliac artery which goes to the genitals and legs.
The arteries are further divided into arterioles and then into capillaries. These capillaries are numerous in number and they join together and form venules which further joins and forms veins.

Deoxygenated Blood

Now as soon as the oxygenated blood reaches all parts of the body, second part of the systemic blood circulation pathway starts. This is the process of taking the deoxygenated blood from different parts of the body to the heart for further purification and oxygenation.
The deoxygenated blood from the head and the neck region is brought by the jugular vein. From the shoulder region, subclavian vein brings the blood. Both of these veins further join and form major vein known as superior vena cava.
From the lower portion of the body, renal vein carries the blood form the kidney, hepatic vein from the liver and iliac vein from the genitals and legs. These veins further join together to form inferior vena cava.
The vena cava takes the deoxygenated blood to the right auricle of the heart which is further sent to the lungs for purification. The process is repeated and a normal blood circulation is maintained in all the parts of the body.
Throughout the circulation pathway, the blood takes absorbed food from the intestinal wall and distributes oxygen and nutrients to each cell and when the blood passes through the kidney all the nitrogenous wastes are removed from the blood. This keeps purifying the blood apart from oxygenating.
Our body is totally dependent on the circulatory systems for nutrients, energy and oxygen and systemic circulation is one of the most important part of this system.