How Much Do You Know of Your Circulatory System?


One of the most active body systems among the rest is the circulatory system. It is a critical body system responsible for your well being since its vital component is blood or 'life.'

What is the Circulatory System?

The circulatory system definition sums up into a few words. It is a system that circulates blood when transporting nutrients, oxygen and other vital body essentials while removing wastes.

The activity of the circulatory system begins when the small intestine passes food nutrients into the blood. Also, for the oxygen, it starts when you breathe, and oxygen enters through your nostrils or mouth to the lungs. The blood from the heart enters the lungs for oxygenation to which the system distributes to all the body's cells and tissues.

Amazing Facts of Circulatory System

The most intricate system among all the body systems is the circulatory system. It involves numerous complex activities that make up the system. Surprisingly, the length of all the arteries, veins, capillaries in an average adult equals to going around the planet earth two and a half times.

If you can join every blood vessel one to another end-to-end and stretch it out, it can cover a distance of approximately 100,000 kilometers (60,000 miles).

As if that is not enough, the blood circuit from the heart, lungs, and back to the heart can take only six seconds.

Circulatory System Organs

The circulatory system has four key features that play significant roles to ensure your body is well-nourished and healthy. It is useful for the distribution of nutrients and other vital products your body needs for growth and maintenance.

The Heart

The heart is an essential part of the circulatory system without which you cannot live. It sits at the center of the chest between the two lungs, tilting slightly to the left side.

The heart is the organ at the center of circulatory system activities. Every activity of the circulatory system begins and ends with the heart. Also, the entire body's organs and tissues depend on the heart organ for pumping out nutrients and oxygen-rich blood. The organ has two divisions that work differently from one another.

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The Heart's Right Side

The heart right side deals with deoxygenated blood containing carbon dioxide that comes from the body cells as waste.

The oxygen-depleted blood enters the atrium (the right upper part of the heart) through anterior and posterior vena cava veins. The atrium then pumps the blood into its lower side, the right ventricle through the tricuspid valve. Once the ventricle is full of blood, the valve closes to prevent blood back-flow into the atrium.

The right ventricle releases the blood through the pulmonic valve and into the pulmonary artery for delivery into the lungs for oxygenation.

The Heart's Left Side

From the lungs, the oxygenated blood enters the pulmonary vein for delivery to the entire body through the heart. The blood enters the left atrium and then leaves to flow into the left ventricle through the mitral valve.

Just like on the right side, the mitral valve closes when the left ventricle fills up with blood to prevent flow back to the atrium. The blood then leaves the left ventricle and enters the aorta through the aortic valve.

The aortic valve closes once the blood has passed through to prevent flow-back. The aorta then delivers the blood to the body through otherThe Blood

The blood is the means of transport the heart uses to deliver nutrients, oxygen and everything else the body needs. Without which the body would not have nourishment to keep it healthy.

Your blood forms in different components to perform various tasks:

  • Plasma - The fluid matter that holds the red blood cells, the white blood cells, the platelets, and other numerous cells together to make up blood. The fluid which is 55 percent of the blood contains water, enzymes, salts, proteins, and antibodies
  • Red Blood Cells – The red blood cells (RBC), Calso called erythrocytes, contain a protein called hemoglobin. Hemoglobin permits the transportation of nutrients and oxygen to the rest of the body and carbon dioxide from the body tissues.
  • Hemoglobin pigments the cells to their natural red color. The hemoglobin is also the means your doctor can use to check your blood level.
  • White Blood Cells – The white blood cells (WBC), also known as leucocytes or leukocytes, come from the stem cells of the bone marrow. They are vital cells in providing immunity to the body. The WBCs prevent harmful invaders and protects and fight off diseases.
  • Platelets – Another name for platelets is thrombocytes.

Along with the white blood cells, the bone marrow produced the platelets as well. The function of the platelets is to coagulate or clot the blood to stop bleeding when one of the blood vessels gets damaged. The injured blood vessel then alerts the platelets through signals to seal the bleeding through coagulation or clot formation.


The arteries are the passage the blood uses to deliver the nutrients, oxygen, and other supplies to the rest of the body.


The veins are the reverse route the blood pass when moving back to the heart. This time the blood carries the deoxygenated blood to the heart.

What Are the Circulatory System Functions?

Circulation uses blood to transfer nutrients, oxygen and hormones to the body cells. The system also carries wastes from the body cells such as carbon dioxide to expel through the lungs.

The circulatory system adapts to the condition of the body. During exercise, your heart pumps more hard and fast to feed your skeletal muscle cells with sufficient oxygen. Likewise, during infection, the system supplies enough immune cells to curb the disease.

It is also the responsibility of the circulatory system to assist other body systems in facilitating their functions. For instance:

  • The digestive system - the circulatory system receives the absorbed nutrients for transportation to all parts of the body. (Read about the digestive system in our body systems series)
  • The immune system - the circulatory system provides the immune system with white blood cells and antibodies to form an immunity. (Follow the immune system in our coming body systems series)
  • Lymphatic system – the circulatory system extends to the lymphatic system by providing plasma fluid to form the lymphatic fluid. (Follow the lymphatic system in our coming body systems series)
  • Three Circulatory System Circuits

    The circulatory system network has three different secondary circuits that cover the entire blood circulation of the body.

    The Systemic Circulation

    The systemic circulation is responsible for supplying the whole body with oxygenated blood. It also includes waste removal such as carbon dioxide from the body cells.

    It starts with the heart pumping the oxygenated blood out through the left ventricle into the aorta. From the heart, the system takes oxygenated blood and nutrients to every body cell. In the return circuit, the system brings back deoxygenated blood for oxygen refill by the lungs.

    The deoxygenated blood enters the heart through the right atrium. From the right atrium, the blood moves into the right ventricle and then to the pulmonary artery for the pulmonary circulation.

    Pulmonary Circulation or Circulatory System of the Lung

    The pulmonary circuit is short compared to the other two circulations. From the right ventricle, the blood containing carbon dioxide enters the pulmonary arteries. The blood then moves through pulmonary arteries to enter into the lungs.

    The lungs clean the blood of waste gas, carbon dioxide and in its stead provides clean oxygen. From the lungs, the oxygenated blood goes through the pulmonary vein back to the left atrium. 

    From the left atrium, the blood enters the left ventricle. The oxygenated blood then leaves the heart through the aorta artery to again begin the systemic circulation.

    Coronary Circulation

    Coronary circulation is highly essential since it supplies the most vital organ that keeps you alive, which is the heart. Your heart, just like other body tissues and cells, needs oxygen to function. The Coronary arteries take care of the heart muscle by supplying it with oxygen-rich blood.

    The cardiac veins then remove the oxygen-depleted blood from the heart muscle. For the heart to continue working efficiently, the coronary circulation must be apt in both supplying and depletion functions.

    The coronary circulation operates with two main coronary arteries that branch off from the main artery, which is aorta. The two coronary arteries further branch off into smaller arteries that nourish and oxygenate the heart muscles.

    The two coronary arteries which work together to enhance a healthy heart are:

    Left Main Coronary Artery of LMCA

    The artery is responsible for supplying oxygen-rich blood to the heart muscle on the left side – left atrium and left ventricle.

    The left main artery further branches out to form the left anterior descending artery. The left anterior takes care of the blood supply to the heart's front-left side.

    Another branch from the left coronary artery is the circumflex artery. The branch artery surrounds the muscle of the heart from outside. The activity of the left coronary artery is to supply blood to the outer side of the heart.

    Right Coronary Artery or RCA

    The right coronary artery is the supplier of oxygenated blood and nutrients to the right side of the heart. It services the right atrium, right ventricle, sinoatrial node or sinus node (for muscles contraction), and atrioventricular node (regulating the heart rhythm).

    Despite everything working right for the circulatory system, some health conditions can interfere with the smooth running of the system. Some of the diseases, if left untreated, can lead to other severe health conditions or can be fatal. 

    Atherosclerosis is where arteries clog with fatty deposits that stick together to form plaque on their lining.

    Common Diseases for Circulatory System

    The circulatory system is not different from other body systems and therefore, can be susceptible to diseases. Some of the circulatory system diseases include:

    Coronary Artery Disease or Atherosclerosis

    The condition hardens the arteries that deliver oxygenated blood to the heart from the lungs. The arteries clog with fatty deposits that stick together to form plaque on its lining. Atherosclerosis can cause high blood pressure and other serious heart diseases.

    Arrhythmia Disease

    Abnormal heart rhythms and heart rate is an arrhythmia. Some heart conditions such as hypertension or valves disorder can lead to the disease.

    Mitral Valve Prolapse and Mitral Stenosis

    The two are conditions of the mitral valve. The mitral valve is the atrioventricular valve that connects the left atrium to the left ventricle. It shuts the connection to prevent blood flowing back to the atrium when the ventricle fills up.

    Sometimes the valve can bulge backwards to the atrium during the heart's contraction when pumping, a condition known as mitral valve prolapse (MVP). Also, the mitral valve can narrow abnormally preventing the smooth flow of blood from the atrium to the ventricle. The two conditions can affect the circulatory system.

    Cardiac Ischemia

    Some conditions such as blood clots or atherosclerosis can cause cardiac ischemia also known as myocardial ischemia. When your heart muscles fail to get the required amount of oxygen, it weakens the heart and hence affecting the circulatory system.

    Peripheral Artery Disease

    The peripheral artery disease, also known as PAD. It affects the blood vessels that serve other parts of the body away from the heart or brain. Any of the blood vessels can narrow and therefore, reducing the flow of blood. Such occurrence can affect and damage the body cells.


    After walking through the circulatory system, you can concur that it is a non-stop intricate maze of networks and activities. Despite the complexity of the network, the circulatory system plays a significant role to keep you nourished, healthy and alive.

    However, the system is sensitive to health conditions which can adversely affect your whole being. Taking care of the circulatory system is, therefore not a choice but mandatory. The food you eat and your lifestyle can highly contribute to either managing or damaging the circulatory system.

    Some of the system's disease encroach silently to erupt when in advance stage. It is essential to check your circulatory system as a whole periodically to curb such 'silent killing' diseases.

    About YOUR Circulatory System

    At Island Healthworks Clinic, we use modern technology to check blood and other tests to arrest some of the circulatory system diseases for early treatment.

    Do you need to talk to us about your health? Call us now at 250.468.7685.

    For consultation and other health services, talk to our Natural Health Practitioner, Yvonne Dollard Perc. You can also write to us at This email address is being protected from spambots. You need JavaScript enabled to view it..

    Visit our website for the next part of our body system series. You wouldn't want to miss out on any of the series.

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    This article is intended for educational purposes and the information contained within is not intended to treat, diagnose or cure any disease or health problem. Please seek appropriate medical attention for any health complaints. We cannot take responsibility for your health care decisions. Our intent is only to offer health information to help you with your search for better health. 

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    Tuesday, 07 July 2020