A Level Biology Revision "The Human Circulatory System"

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Blood is pumped from the heart through arteries at high pressure, which decreases as it moves through the body and returns to the heart through veins for gas exchange. Organs receive oxygenated blood through arteries and release deoxygenated blood through veins, completing the circulation process.

Insights

  • Arteries carry blood away from the heart under high pressure, with the pulmonary artery directing deoxygenated blood to the lungs and the aorta delivering oxygenated blood to body organs, named after the supplied organ.
  • Capillaries facilitate gas exchange in organs, allowing oxygen to move to body cells and carbon dioxide to return to the blood, which is then carried back to the heart by veins, except for the pulmonary vein that transports oxygenated blood from the lungs to the heart.

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Recent questions

  • What is the function of arteries?

    Carry blood away from the heart under pressure.

  • How does gas exchange occur in the body?

    Oxygen diffuses into body cells, carbon dioxide back to blood.

  • What is the role of veins in the circulatory system?

    Carry oxygenated blood away from organs to the heart.

  • How does the pulmonary artery differ from the pulmonary vein?

    Pulmonary artery carries deoxygenated blood, vein carries oxygenated.

  • What is the purpose of the aorta in the circulatory system?

    Carries oxygenated blood from the heart to body organs.

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Summary

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Blood Circulation in the Human Body

  • Blood leaves the heart in arteries, under high pressure that increases with each heart contraction, known as the pulse. The pulmonary artery carries deoxygenated blood to the lungs, while the aorta carries oxygenated blood to the body organs, with individual arteries named based on the supplied organ, such as the renal arteries serving the kidneys.
  • Oxygenated blood passes through capillaries in organs for gas exchange, with oxygen diffusing to body cells and carbon dioxide back into the blood. Veins then carry the oxygenated blood away from organs towards the heart, with the vena cava ultimately returning deoxygenated blood back to the heart, except for the pulmonary vein transporting oxygenated blood from the lungs to the heart.
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