When the muscles contract, the valves open up to allow the blood to flow from the right atrium to right ventricle and from the left atrium to left ventricle. When the valves relax they close to prevent the blood from flowing backwards. This is the process carried out by the heart to pump the blood throughout the body.
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The blood needing oxygen is pumped out of the right ventricle, through the pulmonary valve into the pulmonary artery. The pulmonary artery then divides into the right and left pulmonary arteries, carrying blood to the right and left lungs.
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The tubes or the blood vessels called veins and arteries carry blood to and from the heart respectively. The blood present in the heart is pumped through chambers.
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Enlarge Image. Heart is the most important organ in the human body. It is a little larger than your fist, and is located to the left of the middle of the chest. It is nothing but a pump, composed of muscles which pump blood to each and every part of the body.
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Your heart pumps all day to circulate blood around the body. On average, a red blood cell in the circulation will pass through the heart every 45 seconds. If you start to exert yourself your heart will start to pump faster to supply your working muscles with the increased amount of oxygen and nutrients they need.
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Your heart is made up of 2 pumps. The pump on the right hand side receives blood that has already delivered its oxygen round the body and sends this blood to the lungs to pick up more oxygen (and get rid of carbon dioxide).
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The purpose of your heart is to pump blood to the organs and tissues of your body that need the oxygen and nutrients it carries. Oxygen-rich blood is pumped out of the left side of your heart (shown on the right in the diagram) into the arteries to these tissues and organs.
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1 Veins. 2  These are blood vessels that take blood back to the heart; this blood has lower oxygen content and is rich in waste products that are to be excreted or removed from the body.
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As the heart beats, it pumps blood through a system of blood vessels, called the circulatory system. The vessels are elastic, muscular tubes that carry blood to every part of the body. Blood is essential.
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A. The heart is an amazing organ. It pumps oxygen and nutrient-rich blood throughout the body to sustain life. This fist-sized powerhouse beats (expands and contracts) 100,000 times per day, pumping five or six quarts of blood each minute, or about 2,000 gallons per day.
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what makes the heart pump blood
The heart pumps blood through a system of blood vessels, called the circulatory system.