How Your Circulatory System Works
This system pumps blood from your heart through your body.
Encyclopædia Britannica, Inc.
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Encyclopædia Britannica, Inc.In a circuit through the cardiovascular system, red blood cells transport oxygen from the lungs to the body tissues and transport carbon dioxide from the body tissues to the lungs.
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Encyclopædia Britannica, Inc.Hemoglobin is an example of a globular protein. Learn how hemoglobin proteins in the blood transport oxygen from the lungs to tissues throughout the body.
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Encyclopædia Britannica, Inc.Are you “red-y” to find out?
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Encyclopædia Britannica, Inc.The heart, located between the lungs, powers the circulatory system.
Transcript
The circulatory system cycles blood through your body to deliver vital oxygen to its tissues. There are two distinct blood flow loops in the system—the systemic circulation and the pulmonary circulation.
The systemic circulation carries blood throughout the body. At its center is your heart, composed of four chambers. The left and right ventricles pump blood out of the heart. The left and right atria receive blood into the heart. Arteries are blood vessels that carry pumped blood away from the heart. Veins are blood vessels that return blood to the heart.
To pump blood into and out of the chambers, your heart’s muscles contract and relax over and over. This causes the lub-dub of your heartbeat.
Listen!
Blood travels from the heart to your tissues, where it releases oxygen and picks up carbon dioxide. Then it moves back to the heart and enters the pulmonary circulation.
The pulmonary circulation runs between the lungs and the heart. In this loop, deoxygenated blood returned to the heart by the veins is pumped into the lungs. Once there, your blood gets rid of carbon dioxide and stocks up on oxygen. Then the oxygenated blood flows back into your heart so it can enter the systemic circulation loop again.
About one minute is all it takes for blood to cycle from the heart to the lungs, back to the heart, then to the tissues and back to the heart once more.
The systemic circulation carries blood throughout the body. At its center is your heart, composed of four chambers. The left and right ventricles pump blood out of the heart. The left and right atria receive blood into the heart. Arteries are blood vessels that carry pumped blood away from the heart. Veins are blood vessels that return blood to the heart.
To pump blood into and out of the chambers, your heart’s muscles contract and relax over and over. This causes the lub-dub of your heartbeat.
Listen!
Blood travels from the heart to your tissues, where it releases oxygen and picks up carbon dioxide. Then it moves back to the heart and enters the pulmonary circulation.
The pulmonary circulation runs between the lungs and the heart. In this loop, deoxygenated blood returned to the heart by the veins is pumped into the lungs. Once there, your blood gets rid of carbon dioxide and stocks up on oxygen. Then the oxygenated blood flows back into your heart so it can enter the systemic circulation loop again.
About one minute is all it takes for blood to cycle from the heart to the lungs, back to the heart, then to the tissues and back to the heart once more.