This KS3 Science quiz takes a look at the circulatory system. The heart pumps blood through our circulatory system so that our cells can receive food and oxygen, and have carbon dioxide and waste removed. Blood is pumped out of the heart by two chambers called ventricles. Both ventricles have strong walls made from muscle tissue. The left ventricle has thicker walls because it pumps the blood round the body - the right ventricle only pumps blood to the lungs. Blood flows away from the heart through arteries. These have strong walls, containing muscle tissue which helps to move the blood along. Blood flows back to the heart through veins. Arteries and veins are joined by capillaries. A capillary is a very tiny blood vessel. Their walls are slightly 'leaky' and can allow oxygen and food out and waste products in.
Blood is a complicated mixture. It contains red blood cells (carry oxygen), white blood cells (to fight infection) and blood plasma. The plasma is the liquid part of blood. The plasma has several functions (jobs), for example, carbon dioxide will dissolve in it and can be carried to the lungs.
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You can find more about this topic by visiting BBC Bitesize - The circulatory system
The lungs are part of the respiratory system. The circulatory system is concerned with transporting the blood round the body. The lungs do not help to transport blood round the body, only the heart and blood vessels do that, the lungs simply allow gases to be exchanged between the air and our blood
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The main artery in the body is called the aorta
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When a doctor or nurse takes a blood sample from a patient, they take it from a vein
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No substances can pass through the artery wall
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They have valves to prevent the blood from flowing back down the vein. If it did, all of your blood would end up in your feet or fingers!
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Their walls are only one cell thick
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Should be platelets, these are cells that help your blood to form a clot when a blood vessel is damaged
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Heart muscle does not get tired which is just as well as you need it to work all day and every day of your life
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Most of the oxygen carried by the blood cells is passed to the cells of the body through the walls of capillaries by the time your blood reaches a vein
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Blood enters the ventricles from the atria
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