The blood circulatory system (cardiovascular system) delivers nutrients and oxygen to all cells in the body. It is made up of the heart and the blood vessels running through the entire body. The arteries carry blood away from the heart; the veins carry it back to the heart. The system of blood vessels resembles a tree: The “trunk” – the main artery (aorta) – branches into large arteries, which lead to smaller and smaller vessels. The smallest arteries end in a network of tiny vessels known as the capillary network.
There are actually two blood circulatory systems in our bodies which are connected. Systemic circulation provides organs, tissues and cells with blood so that they get oxygen and other vital substances. Pulmonary circulation is where the fresh oxygen we breathe in enters the blood. At the same time, carbon dioxide is released from the blood.
Blood circulation starts when the heart relaxes between two heartbeats: The blood flows from both atria (the upper two chambers of the heart) into the ventricles (the lower two chambers), which then expand. The next step is when both ventricles pump the blood into the large arteries.
As your heart pumps blood, four valves open and close to make sure blood flows in the correct direction. As they open and close, they make two sounds that create the sound of a heartbeat. The four valves are the aortic valve, mitral valve, pulmonary valve and tricuspid valve.
There are actually two blood circulatory systems in our bodies which are connected. Systemic circulation provides organs, tissues and cells with blood so that they get oxygen and other vital substances. Pulmonary circulation is where the fresh oxygen we breathe in enters the blood. At the same time, carbon dioxide is released from the blood.
Blood circulation starts when the heart relaxes between two heartbeats: The blood flows from both atria (the upper two chambers of the heart) into the ventricles (the lower two chambers), which then expand. The next step is when both ventricles pump the blood into the large arteries.
As your heart pumps blood, four valves open and close to make sure blood flows in the correct direction. As they open and close, they make two sounds that create the sound of a heartbeat. The four valves are the aortic valve, mitral valve, pulmonary valve and tricuspid valve.
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