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Digestion and food

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

11 cards · Science

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

Checked by the Brain Zap team · reviewed 27 Oct 2026

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

Preview

  • Enzyme in saliva that starts breaking down starch

    Show answer: Enzyme in saliva that starts breaking down starch

    Amylase

    Learn more: Amylase splits starch into sugars, which is why bread starts to taste sweet in your mouth.

  • Tube that carries food from mouth to stomach

    Show answer: Tube that carries food from mouth to stomach

    Oesophagus

    Learn more: Waves of muscle, called peristalsis, push food down, so you can even swallow upside down.

  • Flap that stops food going into the windpipe

    Show answer: Flap that stops food going into the windpipe

    Epiglottis

    Learn more: When it doesn't close in time, food goes "down the wrong way" and you cough it back up.

  • Finger-like folds lining the small intestine

    Show answer: Finger-like folds lining the small intestine

    Villi

    Learn more: Millions of villi, each covered in tinier microvilli, give the gut a huge surface to absorb food.

  • Main job of the large intestine

    Show answer: Main job of the large intestine

    Absorbing water

    Learn more: Its bacteria also make some vitamins, such as vitamin K.

About this topic

Digestion starts in your mouth, where saliva begins breaking down starch, and ends many hours later in the large intestine. On the way, muscle waves push food along, enzymes split it into small pieces, and millions of tiny folds absorb what your body needs. This chapter follows that journey and the nutrients it delivers: protein to build muscle, fibre to keep things moving, and the vitamins and minerals whose lack causes scurvy, rickets or anaemia.

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 11 cards

  1. Enzyme in saliva that starts breaking down starch

    Amylase

    Learn more: Amylase splits starch into sugars, which is why bread starts to taste sweet in your mouth.

  2. Tube that carries food from mouth to stomach

    Oesophagus

    Learn more: Waves of muscle, called peristalsis, push food down, so you can even swallow upside down.

  3. Flap that stops food going into the windpipe

    Epiglottis

    Learn more: When it doesn't close in time, food goes "down the wrong way" and you cough it back up.

  4. Finger-like folds lining the small intestine

    Villi

    Learn more: Millions of villi, each covered in tinier microvilli, give the gut a huge surface to absorb food.

  5. Main job of the large intestine

    Absorbing water

    Learn more: Its bacteria also make some vitamins, such as vitamin K.

  6. Nutrient the body uses to build and repair muscle

    Protein

    Learn more: Digestion breaks it into amino acids, which your cells build into new proteins.

  7. Part of plant food that we can't digest

    Fibre

    Learn more: Even undigested, it feeds gut bacteria and keeps food moving, lowering the risk of bowel disease.

  8. Nutrient with the most energy per gram

    Fat

    Learn more: Fat holds about 9 kcal a gram; carbohydrate and protein hold about 4.

  9. Vitamin whose lack causes scurvy

    Vitamin C

    Learn more: Without it gums bleed and wounds won't heal; British sailors were given lime juice to prevent it.

  10. Vitamin your skin makes in sunlight

    Vitamin D

    Learn more: Without enough of it, bones grow soft, as in rickets.

  11. Mineral needed to make haemoglobin

    Iron

    Learn more: Too little means fewer red blood cells, called anaemia, which leaves you tired and pale.

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