The myocardium does the main pumping work: It relaxes to fill with blood and then squeezes contracts to pump the blood.
After pumping, your heart relaxes and fills with blood. The muscle must be able to relax enough so that it can fill with blood properly before it pumps again. The health of your heart muscle affects both its contractility and its ability to relax, both of which determine whether your heart is able to pump enough blood each time it beats. Problems with the contractility of your heart can be caused by problems with the muscle itself such as a viral infection of the heart muscle or an inherited heart muscle disorder or by problems with the blood supply to the heart muscle such as reduced blood flow to the heart muscle, called ischemia.
Your heart muscle needs its own supply of blood because, like the rest of your body, it needs oxygen and other nutrients to stay healthy. For this reason, your heart pumps oxygen-rich blood to its own muscle through your coronary arteries.
Keep blood flowing efficiently. Your heart has four valves that control the flow of blood in and out of the chambers. There are valves between the atrium and the ventricle on each side of your heart.
There is also a valve controlling the flow of blood out of each of your ventricles. The valves are designed to keep blood flowing forward only. When each chamber contracts, a valve opens to allow blood to flow out. When the chamber relaxes, the valve closes to prevent blood from leaking back into the chamber and to allow the chamber to fill with blood again.
A problem with your heart valves can disrupt the normal flow of blood and cause problems for your heart. Related Information Electrical System of the Heart. Blood flow itself is equally complex, involving a cyclic series of steps that move blood trough the heart and to the lungs to be oxygenated, deliver it throughout the body, then bring blood back to the heart to re-start the process.
This is the key function of the cardiovascular system : consuming, transporting, and using oxygen throughout physical activity which includes when you are at rest.
Disruptions in blood flow through the heart and lungs can have serious effects. The heart has two upper chambers—the left and right atriums—and two larger lower chambers—the left and right ventricles.
A series of valves control blood flow in and out of these chambers. Electrical impulses, controlled by the cardiac conduction system , make the heart muscle contract and relax, creating the rate and rhythm of your heartbeat.
Arteries generally transport oxygen-rich blood. The pulmonary artery is unique: It is the only artery in the human body that carries oxygen-poor blood. It would be like pumping up a flat tire with a huge hole in it: No matter the effort you put into pumping, the tire would never inflate. In the case of the heart, blood would come into the chamber and just slosh through it, exiting out the valve at the bottom or upward in the wrong direction each time the ventricle tried to pump blood.
All four of the heart valves open and close at just the right times to keep the blood flowing through the heart in the right direction. Part of the sound of your heartbeat is valves closing. A healthy heart normally beats anywhere from 60 to 70 times per minute when you're at rest. This rate can be higher or lower depending on your health and physical fitness; athletes generally have a lower resting heart rate, for example.
Your heart rate rises with physical activity, as your muscles consume oxygen while they work. The heart works harder to bring oxygenated blood where it is needed. Disrupted or irregular heartbeats can affect blood flow through the heart. This can happen in multiple ways:. If you experience an irregular heartbeat or cardiac symptoms like chest pain and shortness of breath, seek medical help immediately.
Healthy blood flow is critical to overall health. Physical activity is one of the best ways to achieve and maintain optimal functioning of your heart and lungs. If you have health issues, partner with your healthcare provider on the best way to keep your heart rate and rhythm—and therefore, your blood flow—healthy. It's one of the most important things you can do for a long life. What Does the Heart Do? What Does the Circulatory System Do? What Are the Parts of the Heart?
The heart has four chambers — two on top and two on bottom: The two bottom chambers are the right ventricle and the left ventricle. These pump blood out of the heart. A wall called the interventricular septum is between the two ventricles. The two top chambers are the right atrium and the left atrium. They receive the blood entering the heart. A wall called the interatrial septum is between the atria.
The atria are separated from the ventricles by the atrioventricular valves: The tricuspid valve separates the right atrium from the right ventricle.
The mitral valve separates the left atrium from the left ventricle. Two valves also separate the ventricles from the large blood vessels that carry blood leaving the heart: The pulmonic valve is between the right ventricle and the pulmonary artery, which carries blood to the lungs. The aortic valve is between the left ventricle and the aorta, which carries blood to the body. What Are the Parts of the Circulatory System? Two pathways come from the heart: The pulmonary circulation is a short loop from the heart to the lungs and back again.
The systemic circulation carries blood from the heart to all the other parts of the body and back again. In pulmonary circulation: The pulmonary artery is a big artery that comes from the heart.
It splits into two main branches, and brings blood from the heart to the lungs. These muscles allow the body to precisely control when capillary beds receive blood flow. At any given moment, only about percent of our capillary beds actually have blood flowing through them. After the blood has passed through the capillary beds, it enters the venules, veins, and finally the two main venae cavae singular, vena cava that take blood back to the heart. The flow rate increases again, but is still much slower than the initial rate in the aorta.
Blood primarily moves in the veins by the rhythmic movement of smooth muscle in the vessel wall and by the action of the skeletal muscle as the body moves. Because most veins must move blood against the pull of gravity, blood is prevented from flowing backward in the veins by one-way valves. Thus, because skeletal muscle contraction aids in venous blood flow, it is important to get up and move frequently after long periods of sitting so that blood will not pool in the extremities.
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