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All cells in the body need to have oxygen and nutrients, and they need their wastes removed. These are the main roles of the circulatory system. The heart, blood and blood vessels work together to service the cells of the body. Using the network of arteries, veins and capillaries, blood carries carbon dioxide to the lungs (for exhalation) and picks up oxygen. From the small intestine, the blood gathers food nutrients and delivers them to every cell.
Blood vesselsBlood vessels have a range of different sizes and structures, depending on their role in the body.ArteriesOxygenated blood is pumped from the heart along arteries, which are muscular. Arteries divide like tree branches until they are slender. The largest artery is the aorta, which connects to the heart and picks up oxygenated blood from the left ventricle. The only artery that picks up deoxygenated blood is the pulmonary artery, which runs between the heart and lungs.CapillariesThe arteries eventually divide down into the smallest blood vessel, the capillary. Capillaries are so small that blood cells can only move through them one at a time. Oxygen and food nutrients pass from these capillaries to the cells. Capillaries are also connected to veins, so wastes from the cells can be transferred to the blood.VeinsVeins have one-way valves instead of muscles, to stop blood from running back the wrong way. Generally, veins carry deoxygenated blood from the body to the heart, where it can be sent to the lungs. The exception is the network of pulmonary veins, which take oxygenated blood from the lungs to the heart.Blood pressureBlood pressure refers to the amount of pressure inside the circulatory system as the blood is pumped around.Common problemsSome common problems of the circulatory system include:
Where to get help
Things to remember
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Content on this website is provided for information purposes only. Information about a therapy, service, product or treatment does not in any way endorse or support such therapy, service, product or treatment and is not intended to replace advice from your doctor or other registered health professional. The information and materials contained on this website are not intended to constitute a comprehensive guide concerning all aspects of the therapy, product or treatment described on the website. All users are urged to always seek advice from a registered health care professional for diagnosis and answers to their medical questions and to ascertain whether the particular therapy, service, product or treatment described on the website is suitable in their circumstances. The State of Victoria and the Department of Health shall not bear any liability for reliance by any user on the materials contained on this website. The cardiovascular system consists of the heart, blood vessels, and blood. Its primary function is to transport nutrients and oxygen-rich blood to all parts of the body and to carry deoxygenated blood back to the lungs. Abnormalities or injuries to any or all parts of the cardiovascular system can result in serious health complications. Common conditions that can affect the cardiovascular system include coronary artery disease, heart attack, high blood pressure, and stroke. This article explores the cardiovascular system, including its components and their functions. We also outline some common cardiovascular system diseases and their associated treatments. The cardiovascular system is the system responsible for delivering blood to different parts of the body. It consists of the following organs and tissues:
There are two blood circulatory systems in the body. The first is the systemic circulatory system. This is the main blood circulatory system that transports blood to the organs, tissues, and cells throughout the body. The second is the pulmonary circulatory system. This circulatory system moves blood between the heart and lungs. It is where oxygen enters the blood and carbon dioxide leaves the blood. Click on the BodyMap above to interact with a 3D model of the circulatory system. The heart consists of four distinct chambers: two upper chambers called “atria” and two lower chambers called “ventricles.” A wall or “septum” separates the atria and ventricles. Valves control the flow of blood within the different chambers. Blood follows the following path through the heart:
The heart pumps blood through closed vessels to every tissue within the body. The blood itself then delivers nutrients and oxygen to all cells in the body. Without blood, the cells and tissues would not function at their total capacity and would begin to malfunction and die. The cardiac cycle consists of two phases. The first phase is diastole, in which the ventricles fill with blood. It begins when the aortic or pulmonary valve closes and ends when the mitral or tricuspid valve closes. During diastole, blood vessels return blood to the heart in preparation for the next contraction of the ventricles. The second phase is systole, in which the ventricles contract and eject blood. It begins when the mitral or tricuspid valve closes and ends when the aortic or pulmonary valve closes. The pressure inside the ventricles becomes greater than the pressure inside adjacent blood vessels, thereby forcing the blood from the ventricles to the vessels. Cardiovascular diseases can be severe and potentially life threatening. Understanding conditions that can affect the cardiovascular system may help people seek appropriate and timely medical advice. Overviews of some common cardiovascular diseases are below. Heart attackA heart attack happens when a part of the heart muscle does not receive enough blood. This can occur due to a blockage, a tear in an artery around the heart, or if the heart requires more oxygen than is available. Symptoms of a heart attack include:
Three of the main risk factors of a heart attack are:
People who have had a heart attack can lower their chances of future cardiovascular problems by engaging in the following: StrokeA stroke is a medical condition in which the blood supply to a part of the brain becomes cut off. This lack of blood supply triggers the death of brain cells. There are two types of stroke. Ischemic stroke occurs as a result of a blood clot blocking blood flow to the brain. Hemorrhagic stroke occurs as a result of a bleed in or around the brain. Some significant risk factors of a stroke include:
Symptoms of a stroke begin suddenly and may include:
The treatment for stroke will depend on the type. A person who experiences ischemic stroke may receive medications to help break up the blood clot and restore blood flow to their brain. A person who experiences a hemorrhagic stroke may require surgery to fix the blood vessel that is bleeding out. Follow-up treatments for stroke may include:
Heart failureHeart failure occurs when the heart is unable to pump enough blood to satisfy the body’s needs. Some symptoms of heart failure include: Risk factors of heart failure include: There is no cure for heart failure. But treatments can help to slow the progression of the disease and alleviate symptoms. Examples include:
ArrhythmiaAn arrhythmia is an abnormal heart rhythm. It may present as a heartbeat that is too quick, too slow, or has a distinctive pattern. Symptoms may include:
The risk factors of arrhythmia include:
For dangerous arrhythmias, doctors may insert a device called a pacemaker to restore a regular heart rate. As a person ages, their heart begins to work less effectively than it used to. For example, it cannot beat as fast during physical activity, although the resting heart rate remains steady. Arrhythmias can also develop as the heart ages. Another common condition of aging is more stiffness in the large arteries and stiffness of the heart muscle. This stiffness can cause high blood pressure, increasing the risk of heart attacks, stroke, and heart failure. Stiffness of the heart can also cause congestive heart failure. The cardiovascular system consists of the heart, veins, arteries, and capillaries. These components make up two circulatory systems: the systemic and pulmonary circulatory systems. The cardiac cycle consists of two phases: systole (relaxation) and diastole (contraction). Some conditions that can affect the heart include heart attack, stroke, heart failure, and arrhythmia. As the body ages, the heart functions less effectively, especially during periods of high physical activity. The arteries also have a higher likelihood of becoming stiff with age, which increases the possibility of high blood pressure and associated cardiovascular issues. |