HOW THE BLOOD FLOW THROUGH THE BODY

The circulatory system (cardiovascular system) provides nutrients and oxygen to every cell in the body. It consists of the heart and blood vessels that pass through the body. The chute transports blood from the heart. The vein returns it to the heart. The vascular system is similar to a tree: the "main trunk"-the aorta (aorta)-branches into large veins, causing the blood vessels to become smaller and smaller. The smallest arteries terminate in a network of small blood vessels called the capillary network.

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There is not just one circulatory system in the human body, but two interrelated ones: the systemic circulation supplies blood to organs, tissues and cells, allowing them to obtain oxygen and other important substances. The pulmonary circulation is where the fresh oxygen we breathe enters the bloodstream. And carbon dioxide will be out of the blood

Circulation begins when the heart rests between heartbeats: blood flows from the atria (the two upper chambers of the heart) to the ventricles (the two lower chambers), and then the ventricles expand. The next phase is called the excretion phase, when both ventricles pump blood into the aorta.

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In the systemic circulation, the left ventricle pumps oxygen-rich blood into the aorta (aorta). The blood flows from the aorta to larger and larger veins, and then to the capillary network. The blood runs out of oxygen, nutrients and other important substances, and absorbs carbon dioxide and waste products. Now the hypoxic blood is collected in the vein and flows into the right atrium and right ventricle.

This is where pulmonary circulation begins: the right ventricle pumps hypoxic blood into the pulmonary artery, which branches into ever-smaller veins and capillaries. The capillaries form a fine network around the alveoli (the grape-shaped air sacs at the end of the airway). This is where carbon dioxide is released from the blood into the alveoli, where fresh oxygen enters the blood. When we breath out, the carbon dioxide will leaves our bodies. Oxygen-rich blood passes through the pulmonary veins and left atrium into the left ventricle. The next heartbeat starts a new regular cycle.