Routes of Circulation


Circulatory blood flow is segregated into two basic divisions. There is the pulmonary circulation which is in fact complimented by the systemic circulations. Pulmonary circulation consists of those blood vessels which are responsible for the transportation of blood through the lungs for the chance to be oxygenated and return the waste gases picked up along the way and then returned through the body’s blood vessels for the arrival trip back to the heart.

The right ventricle is part of the pulmonary circulation, included for its responsibility of blood expulsion. The pulmonary trunk and the pulmonary valve is also included in the pulmonary circulation as are the pulmonary arteries.

The pulmonary arteries bring the blood which filled with waste gases to the lungs for a gaseous exchange.

The pulmonary capillaries within the individual lungs are responsible for inducing the exchange of waste gases for oxygen. The oxygen rich blood is then transported back to the heart via the pulmonary veins.


Routes of Circulation
Image: Routes Of Circulation

The systemic routes of circulation include every part of the body’s circulatory system which are uninvolved in the pulmonary routes of circulation. The right atrium, the left ventricle, the aortic valve, the aortic branches, all of the capillaries with the exception of those involved with the exchange of gases, and the veins with the exception of the pulmonary veins. The deoxygenated blood that travels back to the heart from the system routes of circulation traverse into the right atrium.


The heart is not only responsible for pumping blood through the entire body, but it also requires its own blood supply in order to perform its function. This is known as coronary circulation. The wall of the heart is equipped with systemic blood vessels dedicated to meeting the heart’s needs for blood supply. The right and left coronary arteries bring oxygenated blood to the myocardium. Along the aorta, where the aortic valve prevents blood flow backwash, the right and left coronary arteries branch off to bring the myocardium the necessary blood supply.

The depression between the atria and the ventricles known as the atrioventricular sulcus carries within it the coronary arteries which encompass the diameter of the heart. From there, two definite branches known as the right and left coronary arteries which bring a fresh blood supply to the atrial and ventricular walls. The interventricular artery branches off the left coronary artery. The interventricular artery follows the same path within the anterior interventricular sulcus bringing the blood supply needed by the ventricles.

The circumflex artery then takes the pathways of blood from there to provide the walls of the left atrium and the walls of the left ventricle with the needed oxygenated blood. The right marginal artery then branches off from the right coronary artery to serve the blood supply needs of the right atrium and the right ventricle. The posterior interventricular artery also branches off of the right coronary artery which runs through the posterior interventricular sulcus to bring the blood supply to both ventricles. Along the posterior surface of the heart the right and the left coronaries come together.

Blood flows into the cardiac veins via the capillaries of the myocardium. These vessels run alongside the coronary arteries sharing the same route. Cardiac veins are distinguishable from the arteries by their thinner walls and their smaller size. The anterior interventricular vein and the posterior cardiac veins are considered the two principle veins. The anterior interventricular vein is responsible for the return of blood from anterior aspect of the heart. The posterior cardiac vein is responsible for the return of the blood from the posterior aspect of the heart. Along the posterior surface of the heart, these two principle veins conjoin together to form the coronary sinus channel. An opening in the right atrium allows the coronary venous blood to re-enter the heart.
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