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Heart, blood and breath

Heart, blood and breath: a chapter of The Human Body Book, with the facts about your own body that are worth knowing.

10 cards · Science

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Each Zap teaches up to 5 new cards, so you learn the deck a few at a time.

Checked by the Brain Zap team · reviewed 26 Oct 2026

Sources: Human body (Encyclopaedia Britannica), Health A to Z (NHS)

Preview

  • Number of chambers in the human heart

    Show answer: Number of chambers in the human heart

    4

    Learn more: The right side pumps blood to the lungs; the left side, with thicker walls, pumps it round the body.

  • Normal adult resting heart rate, in beats a minute

    Show answer: Normal adult resting heart rate, in beats a minute

    60 to 100

    Learn more: Fit athletes can rest below 60; a fast resting rate can be a sign of fever, stress or illness.

  • Vessels that carry blood away from the heart

    Show answer: Vessels that carry blood away from the heart

    Arteries

    Learn more: Their thick, stretchy walls take the push of each heartbeat; veins bring the blood back.

  • Tiny vessels where oxygen passes into the body

    Show answer: Tiny vessels where oxygen passes into the body

    Capillaries

    Learn more: Their walls are one cell thick, so oxygen and food pass through to the cells around them.

  • Protein in red blood cells that carries oxygen

    Show answer: Protein in red blood cells that carries oxygen

    Haemoglobin

    Learn more: It grips oxygen in the lungs and lets it go in the tissues; it is what makes blood red.

About this topic

Every breath brings oxygen into the lungs, where it passes into the blood. The heart, a muscle the size of a fist, pumps that blood through arteries, capillaries and veins to every cell, and back again. At rest, the whole round trip takes about a minute. During exercise, the heart beats faster and harder and you breathe more deeply, so your muscles get the extra oxygen they need.

This is a chapter of The Human Body Book. Each card asks one question, with a hint before you answer and a short reason after. Once you know most of this chapter, the next one starts arriving in your Daily Zap.

All 10 cards

  1. Number of chambers in the human heart

    4

    Learn more: The right side pumps blood to the lungs; the left side, with thicker walls, pumps it round the body.

  2. Normal adult resting heart rate, in beats a minute

    60 to 100

    Learn more: Fit athletes can rest below 60; a fast resting rate can be a sign of fever, stress or illness.

  3. Vessels that carry blood away from the heart

    Arteries

    Learn more: Their thick, stretchy walls take the push of each heartbeat; veins bring the blood back.

  4. Tiny vessels where oxygen passes into the body

    Capillaries

    Learn more: Their walls are one cell thick, so oxygen and food pass through to the cells around them.

  5. Protein in red blood cells that carries oxygen

    Haemoglobin

    Learn more: It grips oxygen in the lungs and lets it go in the tissues; it is what makes blood red.

  6. Blood cells that help stop bleeding

    Platelets

    Learn more: They stick together at a wound and help form a clot that plugs the leak.

  7. Blood cells that fight infection

    White blood cells

    Learn more: Some swallow germs; others make antibodies that mark germs for destruction.

  8. How much blood an average adult has

    About 5 litres

    Learn more: That's about 7% of body weight; the heart pumps all of it round the body about once a minute.

  9. Tiny air sacs in the lungs

    Alveoli

    Learn more: Their walls are very thin and together cover about 70 square metres, so oxygen enters the blood fast.

  10. The muscle under the lungs that drives breathing

    Diaphragm

    Learn more: When it tightens and flattens, the chest grows and air rushes into the lungs.

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